diff --git a/Gemfile b/Gemfile
index f6bcf542f..90a01033b 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,7 +3,7 @@ git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 
 ruby ">= 2.4.10", "< 2.5"
 
-gem "rails", "~> 4.2"
+gem "rails", "~> 5.0.7.2"
 
 gem "devise", "~> 4.0"
 gem "psych", "~> 2.0.2" # part of stdlib, need newer version for safe_load
@@ -24,10 +24,10 @@ gem "loofah", "<= 2.20.0"
 gem "whenever", require: false # for cron jobs
 gem "tilt"
 gem "simple-navigation", "3.11.0"
-gem "simple_form", "3.2.1"
+gem "simple_form", "3.3.1"
 gem "render_anywhere"
 gem "pygments.rb", "~> 2.0"
-gem "ranked-model", "< 0.4.3" # pinned because 0.4.3-0.4.4 are broken (see https://github.com/brendon/ranked-model/issues/139; we also need the fix in https://github.com/brendon/ranked-model/pull/152); we can't update to 0.4.5 yet because it requires activerecord >= 4.2
+gem "ranked-model"
 gem "pdf-reader"
 gem "mechanize"
 gem "prawn"
@@ -43,6 +43,8 @@ gem "ruby-duration"
 gem "pg"
 gem "backup"
 
+gem "activemodel-serializers-xml"
+
 # Redis and Background Processing
 gem "redis"
 gem "qless", github: "Shopify/qless"
@@ -79,7 +81,7 @@ group :development, :test do
 
   gem "standard"
 
-  gem "test_after_commit", "~> 1.2"
+  gem "rails-controller-testing", "~> 1.0"
 end
 
 # Gems used only for assets and not required
diff --git a/Gemfile.lock b/Gemfile.lock
index 094ed9103..fc406a35d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -16,45 +16,52 @@ GIT
 GEM
   remote: https://rubygems.org/
   specs:
-    Ascii85 (1.0.2)
-    actionmailer (4.2.11.3)
-      actionpack (= 4.2.11.3)
-      actionview (= 4.2.11.3)
-      activejob (= 4.2.11.3)
+    Ascii85 (1.1.1)
+    actioncable (5.0.7.2)
+      actionpack (= 5.0.7.2)
+      nio4r (>= 1.2, < 3.0)
+      websocket-driver (~> 0.6.1)
+    actionmailer (5.0.7.2)
+      actionpack (= 5.0.7.2)
+      actionview (= 5.0.7.2)
+      activejob (= 5.0.7.2)
       mail (~> 2.5, >= 2.5.4)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
-    actionpack (4.2.11.3)
-      actionview (= 4.2.11.3)
-      activesupport (= 4.2.11.3)
-      rack (~> 1.6)
-      rack-test (~> 0.6.2)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
+      rails-dom-testing (~> 2.0)
+    actionpack (5.0.7.2)
+      actionview (= 5.0.7.2)
+      activesupport (= 5.0.7.2)
+      rack (~> 2.0)
+      rack-test (~> 0.6.3)
+      rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (4.2.11.3)
-      activesupport (= 4.2.11.3)
+    actionview (5.0.7.2)
+      activesupport (= 5.0.7.2)
       builder (~> 3.1)
       erubis (~> 2.7.0)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
+      rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.3)
-    activejob (4.2.11.3)
-      activesupport (= 4.2.11.3)
-      globalid (>= 0.3.0)
-    activemodel (4.2.11.3)
-      activesupport (= 4.2.11.3)
+    activejob (5.0.7.2)
+      activesupport (= 5.0.7.2)
+      globalid (>= 0.3.6)
+    activemodel (5.0.7.2)
+      activesupport (= 5.0.7.2)
+    activemodel-serializers-xml (1.0.3)
+      activemodel (>= 5.0.0.a)
+      activesupport (>= 5.0.0.a)
       builder (~> 3.1)
-    activerecord (4.2.11.3)
-      activemodel (= 4.2.11.3)
-      activesupport (= 4.2.11.3)
-      arel (~> 6.0)
-    activesupport (4.2.11.3)
-      i18n (~> 0.7)
+    activerecord (5.0.7.2)
+      activemodel (= 5.0.7.2)
+      activesupport (= 5.0.7.2)
+      arel (~> 7.0)
+    activesupport (5.0.7.2)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 0.7, < 2)
       minitest (~> 5.1)
-      thread_safe (~> 0.3, >= 0.3.4)
       tzinfo (~> 1.1)
-    addressable (2.8.1)
-      public_suffix (>= 2.0.2, < 6.0)
+    addressable (2.8.7)
+      public_suffix (>= 2.0.2, < 7.0)
     afm (0.2.2)
-    arel (6.0.4)
+    arel (7.1.4)
     ast (2.4.3)
     atomic (1.1.101)
     avl_tree (1.2.1)
@@ -62,24 +69,26 @@ GEM
     backup (3.4.0)
       open4 (~> 1.3.0)
       thor (>= 0.15.4, < 2)
+    base64 (0.2.0)
     bcrypt (3.1.20)
-    better_errors (2.9.1)
-      coderay (>= 1.0.0)
+    better_errors (2.10.1)
       erubi (>= 1.0.0)
       rack (>= 0.9.0)
-    binding_of_caller (0.7.3)
-      debug_inspector (>= 0.0.1)
-    builder (3.2.4)
-    byebug (9.1.0)
-    capybara (2.17.0)
+      rouge (>= 1.0.0)
+    binding_of_caller (1.0.1)
+      debug_inspector (>= 1.2.0)
+    builder (3.3.0)
+    byebug (11.1.3)
+    capybara (3.32.2)
       addressable
       mini_mime (>= 0.1.3)
-      nokogiri (>= 1.3.3)
-      rack (>= 1.0.0)
-      rack-test (>= 0.5.4)
-      xpath (>= 2.0, < 4.0)
-    capybara-email (2.5.0)
-      capybara (~> 2.4)
+      nokogiri (~> 1.8)
+      rack (>= 1.6.0)
+      rack-test (>= 0.6.3)
+      regexp_parser (~> 1.5)
+      xpath (~> 3.2)
+    capybara-email (3.0.2)
+      capybara (>= 2.4, < 4.0)
       mail
     carrierwave (1.3.2)
       activemodel (>= 4.0.0)
@@ -87,8 +96,7 @@ GEM
       mime-types (>= 1.16)
       ssrf_filter (~> 1.0)
     chronic (0.10.2)
-    chunky_png (1.3.8)
-    coderay (1.1.3)
+    chunky_png (1.4.0)
     coffee-rails (4.2.2)
       coffee-script (>= 2.2.0)
       railties (>= 4.0.0)
@@ -96,39 +104,38 @@ GEM
       coffee-script-source
       execjs
     coffee-script-source (1.12.2)
-    concurrent-ruby (1.2.2)
-    connection_pool (2.2.1)
-    countries (2.1.3)
-      i18n_data (~> 0.8.0)
-      money (~> 6.9)
+    concurrent-ruby (1.3.5)
+    connection_pool (2.2.5)
+    countries (3.1.0)
+      i18n_data (~> 0.11.0)
       sixarm_ruby_unaccent (~> 1.1)
       unicode_utils (~> 1.4)
-    country_select (3.1.1)
-      countries (~> 2.0)
+    country_select (4.0.0)
+      countries (~> 3.0)
       sort_alphabetical (~> 1.0)
-    crass (1.0.5)
+    crass (1.0.6)
     daemons (1.4.1)
-    debug_inspector (0.0.3)
-    devise (4.9.3)
+    debug_inspector (1.2.0)
+    devise (4.9.4)
       bcrypt (~> 3.0)
       orm_adapter (~> 0.1)
       railties (>= 4.1.0)
       responders
       warden (~> 1.2.3)
-    diff-lcs (1.5.0)
+    diff-lcs (1.6.1)
     docile (1.3.5)
     domain_name (0.5.20190701)
       unf (>= 0.0.5, < 1.0.0)
-    erubi (1.12.0)
+    erubi (1.13.1)
     erubis (2.7.0)
     eventmachine (1.2.7)
-    execjs (2.7.0)
-    factory_bot (4.11.1)
-      activesupport (>= 3.0.0)
-    factory_bot_rails (4.11.1)
-      factory_bot (~> 4.11.1)
-      railties (>= 3.0.0)
-    faraday (1.10.3)
+    execjs (2.9.0)
+    factory_bot (5.2.0)
+      activesupport (>= 4.2.0)
+    factory_bot_rails (5.2.0)
+      factory_bot (~> 5.2.0)
+      railties (>= 4.2.0)
+    faraday (1.10.4)
       faraday-em_http (~> 1.0)
       faraday-em_synchrony (~> 1.0)
       faraday-excon (~> 1.1)
@@ -144,33 +151,33 @@ GEM
     faraday-em_synchrony (1.0.0)
     faraday-excon (1.1.0)
     faraday-httpclient (1.0.1)
-    faraday-multipart (1.0.4)
-      multipart-post (~> 2)
-    faraday-net_http (1.0.1)
+    faraday-multipart (1.1.0)
+      multipart-post (~> 2.0)
+    faraday-net_http (1.0.2)
     faraday-net_http_persistent (1.2.0)
     faraday-patron (1.0.0)
     faraday-rack (1.0.0)
     faraday-retry (1.0.3)
-    ffi (1.12.2)
-    foreman (0.84.0)
-      thor (~> 0.19.1)
+    ffi (1.15.5)
+    foreman (0.88.1)
     globalid (0.4.2)
       activesupport (>= 4.2.0)
     has_scope (0.7.2)
       actionpack (>= 4.1)
       activesupport (>= 4.1)
     hashery (2.1.2)
-    hashie (3.5.7)
+    hashie (5.0.0)
     hitimes (1.3.1)
-    http-cookie (1.0.5)
+    http-cookie (1.0.8)
       domain_name (~> 0.5)
-    i18n (0.9.5)
+    i18n (1.14.7)
       concurrent-ruby (~> 1.0)
-    i18n_data (0.8.0)
-    iso8601 (0.10.1)
+    i18n_data (0.11.0)
+    iso8601 (0.13.0)
     json (2.7.6)
     libv8-node (15.14.0.1)
-    loofah (2.3.1)
+    logger (1.5.3)
+    loofah (2.20.0)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.7.1)
@@ -185,28 +192,32 @@ GEM
       ntlm-http (~> 0.1, >= 0.1.1)
       webrick (~> 1.7)
       webrobots (>= 0.0.9, < 0.2)
+    method_source (1.1.0)
     metriks (0.9.9.8)
       atomic (~> 1.0)
       avl_tree (~> 1.2.0)
       hitimes (~> 1.1)
-    mime-types (3.4.1)
+    mime-types (3.6.2)
+      logger
       mime-types-data (~> 3.2015)
-    mime-types-data (3.2023.0218.1)
+    mime-types-data (3.2025.0415)
     mini_mime (1.1.2)
     mini_portile2 (2.4.0)
     mini_racer (0.4.0)
       libv8-node (~> 15.14.0.0)
     minitest (5.15.0)
-    money (6.10.1)
-      i18n (>= 0.6.4, < 1.0)
     multipart-post (2.3.0)
+    mustermann (2.0.2)
+      ruby2_keywords (~> 0.0.1)
     net-http-digest_auth (1.4.1)
-    net-http-persistent (4.0.1)
+    net-http-persistent (4.0.5)
       connection_pool (~> 2.2)
-    newrelic_rpm (4.7.1.340)
+    newrelic_rpm (9.18.0)
+    nio4r (2.7.3)
     nokogiri (1.10.10)
       mini_portile2 (~> 2.4.0)
     ntlm-http (0.1.1)
+    observer (0.1.2)
     open4 (1.3.4)
     orm_adapter (0.5.0)
     parallel (1.20.1)
@@ -214,15 +225,15 @@ GEM
       ast (~> 2.4.1)
       racc
     pdf-core (0.7.0)
-    pdf-reader (2.0.0)
-      Ascii85 (~> 1.0.0)
+    pdf-reader (2.14.1)
+      Ascii85 (>= 1.0, < 3.0, != 2.0.0)
       afm (~> 0.2.1)
       hashery (~> 2.0)
       ruby-rc4
       ttfunk
-    pdfkit (0.8.2)
-    pg (0.21.0)
-    pkg-config (1.5.1)
+    pdfkit (0.8.4.3.2)
+    pg (1.2.3)
+    pkg-config (1.6.1)
     prawn (2.2.2)
       pdf-core (~> 0.7.0)
       ttfunk (~> 1.5)
@@ -232,57 +243,65 @@ GEM
       activesupport (>= 3.0.0)
     pygments.rb (2.3.1)
     racc (1.5.2)
-    rack (1.6.13)
-    rack-protection (1.5.5)
+    rack (2.2.13)
+    rack-protection (2.2.3)
       rack
     rack-test (0.6.3)
       rack (>= 1.0)
-    rails (4.2.11.3)
-      actionmailer (= 4.2.11.3)
-      actionpack (= 4.2.11.3)
-      actionview (= 4.2.11.3)
-      activejob (= 4.2.11.3)
-      activemodel (= 4.2.11.3)
-      activerecord (= 4.2.11.3)
-      activesupport (= 4.2.11.3)
-      bundler (>= 1.3.0, < 2.0)
-      railties (= 4.2.11.3)
-      sprockets-rails
-    rails-deprecated_sanitizer (1.0.4)
-      activesupport (>= 4.2.0.alpha)
-    rails-dom-testing (1.0.9)
-      activesupport (>= 4.2.0, < 5.0)
-      nokogiri (~> 1.6)
-      rails-deprecated_sanitizer (>= 1.0.1)
-    rails-html-sanitizer (1.4.3)
-      loofah (~> 2.3)
-    railties (4.2.11.3)
-      actionpack (= 4.2.11.3)
-      activesupport (= 4.2.11.3)
+    rails (5.0.7.2)
+      actioncable (= 5.0.7.2)
+      actionmailer (= 5.0.7.2)
+      actionpack (= 5.0.7.2)
+      actionview (= 5.0.7.2)
+      activejob (= 5.0.7.2)
+      activemodel (= 5.0.7.2)
+      activerecord (= 5.0.7.2)
+      activesupport (= 5.0.7.2)
+      bundler (>= 1.3.0)
+      railties (= 5.0.7.2)
+      sprockets-rails (>= 2.0.0)
+    rails-controller-testing (1.0.5)
+      actionpack (>= 5.0.1.rc1)
+      actionview (>= 5.0.1.rc1)
+      activesupport (>= 5.0.1.rc1)
+    rails-dom-testing (2.1.1)
+      activesupport (>= 5.0.0)
+      minitest
+      nokogiri (>= 1.6)
+    rails-html-sanitizer (1.5.0)
+      loofah (~> 2.19, >= 2.19.1)
+    railties (5.0.7.2)
+      actionpack (= 5.0.7.2)
+      activesupport (= 5.0.7.2)
+      method_source
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
     rainbow (3.1.1)
-    rake (13.1.0)
-    ranked-model (0.4.0)
-      activerecord (>= 3.1.12)
-    rb-fsevent (0.10.2)
-    rb-inotify (0.9.10)
-      ffi (>= 0.5.0, < 2)
-    recaptcha (4.6.3)
+    rake (13.2.1)
+    ranked-model (0.4.8)
+      activerecord (>= 4.2)
+    rb-fsevent (0.11.2)
+    rb-inotify (0.10.1)
+      ffi (~> 1.0)
+    recaptcha (5.9.0)
       json
-    redcarpet (3.2.3)
+    redcarpet (3.6.1)
     redis (4.4.0)
-    regexp_parser (2.10.0)
+    regexp_parser (1.8.2)
     render_anywhere (0.0.12)
       rails (>= 3.0.7)
-    responders (2.4.1)
-      actionpack (>= 4.2.0, < 6.0)
-      railties (>= 4.2.0, < 6.0)
+    responders (3.0.1)
+      actionpack (>= 5.0)
+      railties (>= 5.0)
     rexml (3.2.5)
-    rmagick (5.1.0)
+    rmagick (5.5.0)
+      observer (~> 0.1)
       pkg-config (~> 1.4)
-    rqrcode (0.10.1)
+    rouge (3.30.0)
+    rqrcode (2.1.2)
       chunky_png (~> 1.0)
+      rqrcode_core (~> 1.0)
+    rqrcode_core (1.2.0)
     rspec-core (3.9.3)
       rspec-support (~> 3.9.3)
     rspec-expectations (3.9.4)
@@ -323,88 +342,94 @@ GEM
     ruby2_keywords (0.0.5)
     rubyzip (1.3.0)
     rusage (0.2.0)
-    sass (3.5.5)
+    sass (3.7.4)
       sass-listen (~> 4.0.0)
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
-    sass-rails (5.0.7)
-      railties (>= 4.0.0, < 6)
-      sass (~> 3.1)
-      sprockets (>= 2.8, < 4.0)
-      sprockets-rails (>= 2.0, < 4.0)
-      tilt (>= 1.1, < 3)
+    sass-rails (6.0.0)
+      sassc-rails (~> 2.1, >= 2.1.1)
+    sassc (2.4.0)
+      ffi (~> 1.9)
+    sassc-rails (2.1.2)
+      railties (>= 4.0.0)
+      sassc (>= 2.0)
+      sprockets (> 3.0)
+      sprockets-rails
+      tilt
     sentry-raven (3.1.2)
       faraday (>= 1.0)
     simple-navigation (3.11.0)
       activesupport (>= 2.3.2)
-    simple_form (3.2.1)
+    simple_form (3.3.1)
       actionpack (> 4, < 5.1)
       activemodel (> 4, < 5.1)
     simplecov (0.18.5)
       docile (~> 1.1)
       simplecov-html (~> 0.11)
-    simplecov-html (0.12.3)
-    sinatra (1.4.8)
-      rack (~> 1.5)
-      rack-protection (~> 1.4)
-      tilt (>= 1.3, < 3)
-    sixarm_ruby_unaccent (1.2.0)
+    simplecov-html (0.13.1)
+    sinatra (2.2.3)
+      mustermann (~> 2.0)
+      rack (~> 2.2)
+      rack-protection (= 2.2.3)
+      tilt (~> 2.0)
+    sixarm_ruby_unaccent (1.2.2)
     sort_alphabetical (1.1.0)
       unicode_utils (>= 1.2.2)
-    spring (1.7.2)
-    sprockets (3.7.2)
+    spring (2.1.1)
+    sprockets (3.7.5)
+      base64
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
-    sprockets-rails (2.3.3)
-      actionpack (>= 3.0)
-      activesupport (>= 3.0)
-      sprockets (>= 2.8, < 4.0)
+    sprockets-rails (3.2.2)
+      actionpack (>= 4.0)
+      activesupport (>= 4.0)
+      sprockets (>= 3.0.0)
     ssrf_filter (1.0.8)
     standard (1.0.5)
       rubocop (= 1.12.1)
       rubocop-performance (= 1.10.1)
     statsd-ruby (1.5.0)
     superfish-rails (1.6.0.1)
-    test_after_commit (1.2.2)
-      activerecord (>= 3.2, < 5.0)
     thin (1.8.2)
       daemons (~> 1.0, >= 1.0.9)
       eventmachine (~> 1.0, >= 1.0.4)
       rack (>= 1, < 3)
-    thor (0.19.4)
+    thor (1.2.2)
     thread_safe (0.3.6)
-    tilt (2.0.8)
-    ttfunk (1.5.1)
+    tilt (2.6.0)
+    ttfunk (1.6.2.1)
     tzinfo (1.2.11)
       thread_safe (~> 0.1)
-    uglifier (4.1.2)
+    uglifier (4.2.1)
       execjs (>= 0.3.0, < 3)
-    unf (0.1.4)
-      unf_ext
-    unf_ext (0.0.8.2)
+    unf (0.2.0)
     unicode-display_width (2.6.0)
     unicode_utils (1.4.0)
     vegas (0.1.11)
       rack (>= 1.0.0)
-    warden (1.2.7)
-      rack (>= 1.0)
-    webrick (1.7.0)
+    warden (1.2.9)
+      rack (>= 2.0.9)
+    webrick (1.9.1)
     webrobots (0.1.2)
-    whenever (0.10.0)
+    websocket-driver (0.6.5)
+      websocket-extensions (>= 0.1.0)
+    websocket-extensions (0.1.5)
+    whenever (1.0.0)
       chronic (>= 0.6.3)
-    will_paginate (3.1.6)
-    world-flags (0.6.5)
+    will_paginate (4.0.1)
+    world-flags (0.6.6)
       hashie (>= 1.2)
       i18n (>= 0.6)
-    xpath (2.1.0)
-      nokogiri (~> 1.3)
+    xpath (3.2.0)
+      nokogiri (~> 1.8)
     yui-compressor (0.12.0)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
+  activemodel-serializers-xml
   backup
   better_errors
   binding_of_caller
@@ -433,8 +458,9 @@ DEPENDENCIES
   pundit (~> 1.1.0)
   pygments.rb (~> 2.0)
   qless!
-  rails (~> 4.2)
-  ranked-model (< 0.4.3)
+  rails (~> 5.0.7.2)
+  rails-controller-testing (~> 1.0)
+  ranked-model
   recaptcha
   redcarpet
   redis
@@ -449,13 +475,12 @@ DEPENDENCIES
   sass-rails
   sentry-raven
   simple-navigation (= 3.11.0)
-  simple_form (= 3.2.1)
+  simple_form (= 3.3.1)
   simplecov
   sinatra
   spring
   standard
   superfish-rails (~> 1.6.0)
-  test_after_commit (~> 1.2)
   tilt
   uglifier (>= 1.0.3)
   whenever
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index cf8424911..cc696d42d 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -4,14 +4,14 @@ class ApplicationController < ActionController::Base
 
   layout "scaffold"
 
+  protect_from_forgery
+
   before_filter :update_last_seen_at
   before_filter :update_contest_checkin
   before_filter :read_settings
   before_filter :check_su_loss
   before_filter :configure_permitted_parameters, if: :devise_controller?
 
-  protect_from_forgery
-
   # helper ApplicationHelper
   # helper ProblemsHelper
   # helper Accounts::RequestsHelper
diff --git a/app/models/request.rb b/app/models/request.rb
index 63fde6e89..ec2432f9f 100644
--- a/app/models/request.rb
+++ b/app/models/request.rb
@@ -31,8 +31,7 @@ class Request < ActiveRecord::Base
   scope :pending, -> { status_pending.merge(not_past_expiry) }
   scope :expired, -> { status_pending.merge(past_expiry) }
 
-  # TODO(Rails5): Convert to where.not(pending).or(past_expiry)
-  scope :closed, -> { where("status != ? OR expired_at <= ?", STATUS[:pending], DateTime.now) }
+  scope :closed, -> { where.not(pending).or(past_expiry) }
 
   def pending?
     status == STATUS[:pending] && (expired_at == Float::INFINITY || expired_at > DateTime.now)
diff --git a/bin/bundle b/bin/bundle
new file mode 100755
index 000000000..66e9889e8
--- /dev/null
+++ b/bin/bundle
@@ -0,0 +1,3 @@
+#!/usr/bin/env ruby
+ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../../Gemfile', __FILE__)
+load Gem.bin_path('bundler', 'bundle')
diff --git a/bin/rails b/bin/rails
new file mode 100755
index 000000000..073966023
--- /dev/null
+++ b/bin/rails
@@ -0,0 +1,4 @@
+#!/usr/bin/env ruby
+APP_PATH = File.expand_path('../config/application', __dir__)
+require_relative '../config/boot'
+require 'rails/commands'
diff --git a/bin/rake b/bin/rake
new file mode 100755
index 000000000..17240489f
--- /dev/null
+++ b/bin/rake
@@ -0,0 +1,4 @@
+#!/usr/bin/env ruby
+require_relative '../config/boot'
+require 'rake'
+Rake.application.run
diff --git a/bin/setup b/bin/setup
new file mode 100755
index 000000000..e620b4dad
--- /dev/null
+++ b/bin/setup
@@ -0,0 +1,34 @@
+#!/usr/bin/env ruby
+require 'pathname'
+require 'fileutils'
+include FileUtils
+
+# path to your application root.
+APP_ROOT = Pathname.new File.expand_path('../../', __FILE__)
+
+def system!(*args)
+  system(*args) || abort("\n== Command #{args} failed ==")
+end
+
+chdir APP_ROOT do
+  # This script is a starting point to setup your application.
+  # Add necessary setup steps to this file.
+
+  puts '== Installing dependencies =='
+  system! 'gem install bundler --conservative'
+  system('bundle check') || system!('bundle install')
+
+  # puts "\n== Copying sample files =="
+  # unless File.exist?('config/database.yml')
+  #   cp 'config/database.yml.sample', 'config/database.yml'
+  # end
+
+  puts "\n== Preparing database =="
+  system! 'bin/rails db:setup'
+
+  puts "\n== Removing old logs and tempfiles =="
+  system! 'bin/rails log:clear tmp:clear'
+
+  puts "\n== Restarting application server =="
+  system! 'bin/rails restart'
+end
diff --git a/bin/update b/bin/update
new file mode 100755
index 000000000..a8e4462f2
--- /dev/null
+++ b/bin/update
@@ -0,0 +1,29 @@
+#!/usr/bin/env ruby
+require 'pathname'
+require 'fileutils'
+include FileUtils
+
+# path to your application root.
+APP_ROOT = Pathname.new File.expand_path('../../', __FILE__)
+
+def system!(*args)
+  system(*args) || abort("\n== Command #{args} failed ==")
+end
+
+chdir APP_ROOT do
+  # This script is a way to update your development environment automatically.
+  # Add necessary update steps to this file.
+
+  puts '== Installing dependencies =='
+  system! 'gem install bundler --conservative'
+  system('bundle check') || system!('bundle install')
+
+  puts "\n== Updating database =="
+  system! 'bin/rails db:migrate'
+
+  puts "\n== Removing old logs and tempfiles =="
+  system! 'bin/rails log:clear tmp:clear'
+
+  puts "\n== Restarting application server =="
+  system! 'bin/rails restart'
+end
diff --git a/config/boot.rb b/config/boot.rb
index edf778b45..282011619 100644
--- a/config/boot.rb
+++ b/config/boot.rb
@@ -1,6 +1,3 @@
-require "rubygems"
+ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../Gemfile", __dir__)
 
-# Set up gems listed in the Gemfile.
-ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../Gemfile", __FILE__)
-
-require "bundler/setup" if File.exist?(ENV["BUNDLE_GEMFILE"])
+require "bundler/setup" # Set up gems listed in the Gemfile.
diff --git a/config/cable.yml b/config/cable.yml
new file mode 100644
index 000000000..0bbde6f74
--- /dev/null
+++ b/config/cable.yml
@@ -0,0 +1,9 @@
+development:
+  adapter: async
+
+test:
+  adapter: async
+
+production:
+  adapter: redis
+  url: redis://localhost:6379/1
diff --git a/config/environment.rb b/config/environment.rb
index 2c9f09cfd..cac531577 100644
--- a/config/environment.rb
+++ b/config/environment.rb
@@ -1,5 +1,5 @@
-# Load the rails application
-require File.expand_path("../application", __FILE__)
+# Load the Rails application.
+require_relative "application"
 
-# Initialize the rails application
-NZTrain::Application.initialize!
+# Initialize the Rails application.
+Rails.application.initialize!
diff --git a/config/environments/production.rb b/config/environments/production.rb
index a3d5c60e5..fc621db9b 100644
--- a/config/environments/production.rb
+++ b/config/environments/production.rb
@@ -22,8 +22,8 @@
   # If you have no front-end server that supports something like X-Sendfile,
   # just comment this out and Rails will serve the files
 
-  # See everything in the log (default is :info)
-  # config.log_level = :debug
+  # Change to "debug" to log everything (including potentially personally-identifiable information!).
+  config.log_level = :info
 
   # Use a different logger for distributed setups
   # config.logger = SyslogLogger.new
diff --git a/config/initializers/application_controller_renderer.rb b/config/initializers/application_controller_renderer.rb
new file mode 100644
index 000000000..89d2efab2
--- /dev/null
+++ b/config/initializers/application_controller_renderer.rb
@@ -0,0 +1,8 @@
+# Be sure to restart your server when you modify this file.
+
+# ActiveSupport::Reloader.to_prepare do
+#   ApplicationController.renderer.defaults.merge!(
+#     http_host: 'example.org',
+#     https: false
+#   )
+# end
diff --git a/config/initializers/assets.rb b/config/initializers/assets.rb
new file mode 100644
index 000000000..0838adaa2
--- /dev/null
+++ b/config/initializers/assets.rb
@@ -0,0 +1,11 @@
+# Be sure to restart your server when you modify this file.
+
+# Version of your assets, change this if you want to expire all your assets.
+Rails.application.config.assets.version = "1.0"
+
+# Add additional assets to the asset load path
+# Rails.application.config.assets.paths << Emoji.images_path
+
+# Precompile additional assets.
+# application.js, application.css, and all non-JS/CSS in app/assets folder are already added.
+# Rails.application.config.assets.precompile += %w( search.js )
diff --git a/config/initializers/filter_parameter_logging.rb b/config/initializers/filter_parameter_logging.rb
new file mode 100644
index 000000000..4a994e1e7
--- /dev/null
+++ b/config/initializers/filter_parameter_logging.rb
@@ -0,0 +1,4 @@
+# Be sure to restart your server when you modify this file.
+
+# Configure sensitive parameters which will be filtered from the log file.
+Rails.application.config.filter_parameters += [:password]
diff --git a/config/initializers/inflections.rb b/config/initializers/inflections.rb
index 9e8b0131f..ac033bf9d 100644
--- a/config/initializers/inflections.rb
+++ b/config/initializers/inflections.rb
@@ -1,10 +1,16 @@
 # Be sure to restart your server when you modify this file.
 
-# Add new inflection rules using the following format
-# (all these examples are active by default):
-# ActiveSupport::Inflector.inflections do |inflect|
+# Add new inflection rules using the following format. Inflections
+# are locale specific, and you may define rules for as many different
+# locales as you wish. All of these examples are active by default:
+# ActiveSupport::Inflector.inflections(:en) do |inflect|
 #   inflect.plural /^(ox)$/i, '\1en'
 #   inflect.singular /^(ox)en/i, '\1'
 #   inflect.irregular 'person', 'people'
 #   inflect.uncountable %w( fish sheep )
 # end
+
+# These inflection rules are supported but not enabled by default:
+# ActiveSupport::Inflector.inflections(:en) do |inflect|
+#   inflect.acronym 'RESTful'
+# end
diff --git a/config/initializers/new_framework_defaults.rb b/config/initializers/new_framework_defaults.rb
new file mode 100644
index 000000000..cbf423a81
--- /dev/null
+++ b/config/initializers/new_framework_defaults.rb
@@ -0,0 +1,25 @@
+# Be sure to restart your server when you modify this file.
+#
+# This file contains migration options to ease your Rails 5.0 upgrade.
+#
+# Once upgraded flip defaults one by one to migrate to the new default.
+#
+# Read the Guide for Upgrading Ruby on Rails for more info on each option.
+
+Rails.application.config.action_controller.raise_on_unfiltered_parameters = true
+
+# Enable per-form CSRF tokens. Previous versions had false.
+Rails.application.config.action_controller.per_form_csrf_tokens = false
+
+# Enable origin-checking CSRF mitigation. Previous versions had false.
+Rails.application.config.action_controller.forgery_protection_origin_check = false
+
+# Make Ruby 2.4 preserve the timezone of the receiver when calling `to_time`.
+# Previous versions had false.
+ActiveSupport.to_time_preserves_timezone = false
+
+# Require `belongs_to` associations by default. Previous versions had false.
+Rails.application.config.active_record.belongs_to_required_by_default = false
+
+# Do not halt callback chains when a callback returns false. Previous versions had true.
+ActiveSupport.halt_callback_chains_on_return_false = true
diff --git a/config/initializers/wrap_parameters.rb b/config/initializers/wrap_parameters.rb
new file mode 100644
index 000000000..bbfc3961b
--- /dev/null
+++ b/config/initializers/wrap_parameters.rb
@@ -0,0 +1,14 @@
+# Be sure to restart your server when you modify this file.
+
+# This file contains settings for ActionController::ParamsWrapper which
+# is enabled by default.
+
+# Enable parameter wrapping for JSON. You can disable this by setting :format to an empty array.
+ActiveSupport.on_load(:action_controller) do
+  wrap_parameters format: [:json]
+end
+
+# To enable root element in JSON for ActiveRecord objects.
+# ActiveSupport.on_load(:active_record) do
+#   self.include_root_in_json = true
+# end
diff --git a/config/puma.rb b/config/puma.rb
new file mode 100644
index 000000000..59d2d1881
--- /dev/null
+++ b/config/puma.rb
@@ -0,0 +1,47 @@
+# Puma can serve each request in a thread from an internal thread pool.
+# The `threads` method setting takes two numbers a minimum and maximum.
+# Any libraries that use thread pools should be configured to match
+# the maximum value specified for Puma. Default is set to 5 threads for minimum
+# and maximum, this matches the default thread size of Active Record.
+#
+threads_count = ENV.fetch("RAILS_MAX_THREADS", 5).to_i
+threads threads_count, threads_count
+
+# Specifies the `port` that Puma will listen on to receive requests, default is 3000.
+#
+port ENV.fetch("PORT", 3000)
+
+# Specifies the `environment` that Puma will run in.
+#
+environment ENV.fetch("RAILS_ENV") { "development" }
+
+# Specifies the number of `workers` to boot in clustered mode.
+# Workers are forked webserver processes. If using threads and workers together
+# the concurrency of the application would be max `threads` * `workers`.
+# Workers do not work on JRuby or Windows (both of which do not support
+# processes).
+#
+# workers ENV.fetch("WEB_CONCURRENCY") { 2 }
+
+# Use the `preload_app!` method when specifying a `workers` number.
+# This directive tells Puma to first boot the application and load code
+# before forking the application. This takes advantage of Copy On Write
+# process behavior so workers use less memory. If you use this option
+# you need to make sure to reconnect any threads in the `on_worker_boot`
+# block.
+#
+# preload_app!
+
+# The code in the `on_worker_boot` will be called if you are using
+# clustered mode by specifying a number of `workers`. After each worker
+# process is booted this block will be run, if you are using `preload_app!`
+# option you will want to use this block to reconnect to any threads
+# or connections that may have been created at application boot, Ruby
+# cannot share connections between processes.
+#
+# on_worker_boot do
+#   ActiveRecord::Base.establish_connection if defined?(ActiveRecord)
+# end
+
+# Allow puma to be restarted by `rails restart` command.
+plugin :tmp_restart
diff --git a/config/secrets.yml b/config/secrets.yml
new file mode 100644
index 000000000..b920e28f9
--- /dev/null
+++ b/config/secrets.yml
@@ -0,0 +1,22 @@
+# Be sure to restart your server when you modify this file.
+
+# Your secret key is used for verifying the integrity of signed cookies.
+# If you change this key, all old signed cookies will become invalid!
+
+# Make sure the secret is at least 30 characters and all random,
+# no regular words or you'll be exposed to dictionary attacks.
+# You can use `rails secret` to generate a secure secret key.
+
+# Make sure the secrets in this file are kept private
+# if you're sharing your code publicly.
+
+development:
+  secret_key_base: 60daf0d06bb2646d9c60f5036ac363a9a4b48c08f02abe474610e58edfa030f944fa7ab17f7a6b06e26327258ef3727c5f95c9634548f475e1347e5f74d2ffe7
+
+test:
+  secret_key_base: b40cbeae7b7995d6e308b6bba2c95d2c3c9701ba9a02b46aea044becb636bd4ecfb32d8078c99f3cf12642ef210cb5dadb2000da184a7b6c241d717f5f714e00
+
+# Do not keep production secrets in the repository,
+# instead read values from the environment.
+production:
+  secret_key_base: <%= ENV["SECRET_KEY_BASE"] %>
diff --git a/config/spring.rb b/config/spring.rb
new file mode 100644
index 000000000..9fa7863f9
--- /dev/null
+++ b/config/spring.rb
@@ -0,0 +1,6 @@
+%w[
+  .ruby-version
+  .rbenv-vars
+  tmp/restart.txt
+  tmp/caching-dev.txt
+].each { |path| Spring.watch(path) }
diff --git a/db/schema.rb b/db/schema.rb
index 8128e87c9..e5a82dd07 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -1,4 +1,3 @@
-# encoding: UTF-8
 # This file is auto-generated from the current state of the database. Instead
 # of editing this file, please use the migrations feature of Active Record to
 # incrementally modify your database, and then regenerate this schema definition.
@@ -34,12 +33,11 @@
     t.integer  "school_year"
     t.integer  "supervisor_id"
     t.boolean  "checked_in",              default: false
+    t.index ["contest_id", "score", "time_taken"], name: "index_contest_relations_on_contest_id_and_score_and_time_taken", order: { score: :desc }, using: :btree
+    t.index ["contest_id", "user_id"], name: "index_contest_relations_on_contest_id_and_user_id", unique: true, using: :btree
+    t.index ["user_id", "started_at"], name: "index_contest_relations_on_user_id_and_started_at", using: :btree
   end
 
-  add_index "contest_relations", ["contest_id", "score", "time_taken"], name: "index_contest_relations_on_contest_id_and_score_and_time_taken", order: {"score"=>:desc}, using: :btree
-  add_index "contest_relations", ["contest_id", "user_id"], name: "index_contest_relations_on_contest_id_and_user_id", unique: true, using: :btree
-  add_index "contest_relations", ["user_id", "started_at"], name: "index_contest_relations_on_user_id_and_started_at", using: :btree
-
   create_table "contest_scores", force: :cascade do |t|
     t.integer  "contest_relation_id", null: false
     t.integer  "problem_id",          null: false
@@ -48,10 +46,9 @@
     t.integer  "attempt"
     t.integer  "submission_id"
     t.datetime "updated_at"
+    t.index ["contest_relation_id", "problem_id"], name: "index_contest_scores_on_contest_relation_id_and_problem_id", using: :btree
   end
 
-  add_index "contest_scores", ["contest_relation_id", "problem_id"], name: "index_contest_scores_on_contest_relation_id_and_problem_id", using: :btree
-
   create_table "contest_supervisors", force: :cascade do |t|
     t.integer  "contest_id"
     t.integer  "user_id"
@@ -111,19 +108,17 @@
     t.string   "filepath",           limit: 255
     t.string   "root_type",          limit: 255
     t.integer  "visibility",         limit: 2,   default: 0
+    t.index ["file_attachment_id"], name: "index_filelinks_on_file_attachment_id", using: :btree
+    t.index ["root_id", "filepath"], name: "index_filelinks_on_root_id_and_filepath", using: :btree
   end
 
-  add_index "filelinks", ["file_attachment_id"], name: "index_filelinks_on_file_attachment_id", using: :btree
-  add_index "filelinks", ["root_id", "filepath"], name: "index_filelinks_on_root_id_and_filepath", using: :btree
-
   create_table "group_contests", force: :cascade do |t|
     t.integer "group_id"
     t.integer "contest_id"
+    t.index ["contest_id", "group_id"], name: "index_group_contests_on_contest_id_and_group_id", using: :btree
+    t.index ["group_id", "contest_id"], name: "index_group_contests_on_group_id_and_contest_id", using: :btree
   end
 
-  add_index "group_contests", ["contest_id", "group_id"], name: "index_group_contests_on_contest_id_and_group_id", using: :btree
-  add_index "group_contests", ["group_id", "contest_id"], name: "index_group_contests_on_group_id_and_contest_id", using: :btree
-
   create_table "group_memberships", force: :cascade do |t|
     t.integer  "group_id"
     t.integer  "member_id"
@@ -134,11 +129,10 @@
     t.integer "group_id"
     t.integer "problem_set_id"
     t.string  "name",           limit: 255
+    t.index ["group_id", "problem_set_id"], name: "index_group_problem_sets_on_group_id_and_problem_set_id", using: :btree
+    t.index ["problem_set_id", "group_id"], name: "index_group_problem_sets_on_problem_set_id_and_group_id", using: :btree
   end
 
-  add_index "group_problem_sets", ["group_id", "problem_set_id"], name: "index_group_problem_sets_on_group_id_and_problem_set_id", using: :btree
-  add_index "group_problem_sets", ["problem_set_id", "group_id"], name: "index_group_problem_sets_on_problem_set_id_and_group_id", using: :btree
-
   create_table "groups", force: :cascade do |t|
     t.string   "name",       limit: 255
     t.datetime "created_at"
@@ -177,10 +171,9 @@
     t.integer  "current_language_id"
     t.datetime "created_at",                      null: false
     t.datetime "updated_at",                      null: false
+    t.index ["identifier"], name: "index_language_groups_on_identifier", unique: true, using: :btree
   end
 
-  add_index "language_groups", ["identifier"], name: "index_language_groups_on_identifier", unique: true, using: :btree
-
   create_table "languages", force: :cascade do |t|
     t.string   "identifier",          limit: 255
     t.string   "compiler",            limit: 255
@@ -198,10 +191,9 @@
     t.string   "interpreter",         limit: 255
     t.string   "interpreter_command", limit: 255
     t.integer  "processes",                       default: 1
+    t.index ["identifier"], name: "index_languages_on_identifier", unique: true, using: :btree
   end
 
-  add_index "languages", ["identifier"], name: "index_languages_on_identifier", unique: true, using: :btree
-
   create_table "organisations", force: :cascade do |t|
   end
 
@@ -217,11 +209,10 @@
     t.integer "problem_id"
     t.integer "problem_set_order"
     t.integer "weighting",         default: 100
+    t.index ["problem_id", "problem_set_id"], name: "index_problem_set_problems_on_problem_id_and_problem_set_id", using: :btree
+    t.index ["problem_set_id", "problem_id"], name: "index_problem_set_problems_on_problem_set_id_and_problem_id", using: :btree
   end
 
-  add_index "problem_set_problems", ["problem_id", "problem_set_id"], name: "index_problem_set_problems_on_problem_id_and_problem_set_id", using: :btree
-  add_index "problem_set_problems", ["problem_set_id", "problem_id"], name: "index_problem_set_problems_on_problem_set_id_and_problem_id", using: :btree
-
   create_table "problem_sets", force: :cascade do |t|
     t.string   "name",                     limit: 255
     t.integer  "owner_id"
@@ -248,10 +239,10 @@
   end
 
   create_table "products", force: :cascade do |t|
-    t.string  "name",        limit: 255
-    t.integer "gtin",        limit: 8
-    t.text    "description"
-    t.string  "image",       limit: 255
+    t.string "name",        limit: 255
+    t.bigint "gtin"
+    t.text   "description"
+    t.string "image",       limit: 255
   end
 
   create_table "requests", force: :cascade do |t|
@@ -289,19 +280,17 @@
     t.text     "data"
     t.datetime "created_at"
     t.datetime "updated_at"
+    t.index ["created_at"], name: "index_sessions_on_created_at", using: :btree
+    t.index ["session_id"], name: "index_sessions_on_session_id", using: :btree
+    t.index ["updated_at"], name: "index_sessions_on_updated_at", using: :btree
   end
 
-  add_index "sessions", ["created_at"], name: "index_sessions_on_created_at", using: :btree
-  add_index "sessions", ["session_id"], name: "index_sessions_on_session_id", using: :btree
-  add_index "sessions", ["updated_at"], name: "index_sessions_on_updated_at", using: :btree
-
   create_table "settings", force: :cascade do |t|
     t.string "key",   limit: 255
     t.string "value", limit: 255
+    t.index ["key"], name: "index_settings_on_key", unique: true, using: :btree
   end
 
-  add_index "settings", ["key"], name: "index_settings_on_key", unique: true, using: :btree
-
   create_table "submissions", force: :cascade do |t|
     t.text     "source"
     t.integer  "score"
@@ -321,21 +310,19 @@
     t.float    "evaluation"
     t.decimal  "points"
     t.integer  "maximum_points"
+    t.index ["problem_id", "created_at"], name: "index_submissions_on_problem_id_and_created_at", using: :btree
+    t.index ["user_id", "problem_id"], name: "index_submissions_on_user_id_and_problem_id", using: :btree
   end
 
-  add_index "submissions", ["problem_id", "created_at"], name: "index_submissions_on_problem_id_and_created_at", using: :btree
-  add_index "submissions", ["user_id", "problem_id"], name: "index_submissions_on_user_id_and_problem_id", using: :btree
-
   create_table "test_case_relations", force: :cascade do |t|
     t.integer  "test_case_id"
     t.integer  "test_set_id"
     t.datetime "created_at",   null: false
     t.datetime "updated_at",   null: false
+    t.index ["test_case_id"], name: "index_test_case_relations_on_test_case_id", using: :btree
+    t.index ["test_set_id"], name: "index_test_case_relations_on_test_set_id", using: :btree
   end
 
-  add_index "test_case_relations", ["test_case_id"], name: "index_test_case_relations_on_test_case_id", using: :btree
-  add_index "test_case_relations", ["test_set_id"], name: "index_test_case_relations_on_test_set_id", using: :btree
-
   create_table "test_cases", force: :cascade do |t|
     t.text     "input"
     t.text     "output"
@@ -345,10 +332,9 @@
     t.integer  "problem_id"
     t.boolean  "sample",                    default: false
     t.integer  "problem_order"
+    t.index ["problem_id", "name"], name: "index_test_cases_on_problem_id_and_name", unique: true, using: :btree
   end
 
-  add_index "test_cases", ["problem_id", "name"], name: "index_test_cases_on_problem_id_and_name", unique: true, using: :btree
-
   create_table "test_sets", force: :cascade do |t|
     t.integer  "problem_id"
     t.integer  "points"
@@ -357,10 +343,9 @@
     t.datetime "updated_at"
     t.boolean  "prerequisite",              default: false
     t.integer  "problem_order"
+    t.index ["problem_id", "name"], name: "index_test_sets_on_problem_id_and_name", unique: true, using: :btree
   end
 
-  add_index "test_sets", ["problem_id", "name"], name: "index_test_sets_on_problem_id_and_name", unique: true, using: :btree
-
   create_table "user_problem_relations", force: :cascade do |t|
     t.integer  "problem_id"
     t.integer  "user_id"
@@ -372,11 +357,10 @@
     t.datetime "first_viewed_at"
     t.datetime "created_at"
     t.datetime "updated_at"
+    t.index ["problem_id", "ranked_score"], name: "index_user_problem_relations_on_problem_id_and_ranked_score", using: :btree
+    t.index ["user_id", "problem_id"], name: "index_user_problem_relations_on_user_id_and_problem_id", unique: true, using: :btree
   end
 
-  add_index "user_problem_relations", ["problem_id", "ranked_score"], name: "index_user_problem_relations_on_problem_id_and_ranked_score", using: :btree
-  add_index "user_problem_relations", ["user_id", "problem_id"], name: "index_user_problem_relations_on_user_id_and_problem_id", unique: true, using: :btree
-
   create_table "users", force: :cascade do |t|
     t.string   "email",                  limit: 255, default: "",    null: false
     t.string   "encrypted_password",     limit: 255, default: "",    null: false
@@ -403,10 +387,10 @@
     t.integer  "school_id"
     t.string   "country_code",           limit: 3
     t.date     "school_graduation"
+    t.index "lower((username)::text)", name: "index_users_on_username", unique: true, using: :btree
+    t.index ["confirmation_token"], name: "index_users_on_confirmation_token", unique: true, using: :btree
+    t.index ["email"], name: "index_users_on_email", unique: true, using: :btree
+    t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true, using: :btree
   end
 
-  add_index "users", ["confirmation_token"], name: "index_users_on_confirmation_token", unique: true, using: :btree
-  add_index "users", ["email"], name: "index_users_on_email", unique: true, using: :btree
-  add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true, using: :btree
-
 end
diff --git a/spec/controllers/problems_controller_spec.rb b/spec/controllers/problems_controller_spec.rb
index 460dffbbd..e852fefce 100644
--- a/spec/controllers/problems_controller_spec.rb
+++ b/spec/controllers/problems_controller_spec.rb
@@ -39,7 +39,7 @@
     it "can post submit for group problem" do
       expect_any_instance_of(Submission).to receive(:judge)
       # post multi-part form
-      post :submit, id: group_problem.id, submission: {language_id: LanguageGroup.find_by_identifier("c++").current_language, source_file: fixture_file_upload("/files/adding.cpp", "text/plain")}
+      post :submit, id: group_problem.id, submission: {language_id: LanguageGroup.find_by_identifier("c++").current_language.id, source_file: fixture_file_upload("/files/adding.cpp", "text/plain")}
       expect(response).to redirect_to submission_path(assigns(:submission))
       expect(assigns(:submission).problem_id).to eq(group_problem.id)
       expect(assigns(:submission).user_id).to eq(user.id)