diff --git a/crystalball.gemspec b/crystalball.gemspec
index 5069d505..48e10502 100644
--- a/crystalball.gemspec
+++ b/crystalball.gemspec
@@ -41,11 +41,12 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'parser'
   spec.add_development_dependency 'pry'
   spec.add_development_dependency 'pry-byebug'
+  spec.add_development_dependency 'psych', '~> 4.0.0'
   spec.add_development_dependency "rake", "~> 10.0"
   spec.add_development_dependency "rspec", "~> 3.0"
   spec.add_development_dependency 'rubocop', ">= 0.56"
   spec.add_development_dependency 'rubocop-rspec'
   spec.add_development_dependency 'simplecov'
-  spec.add_development_dependency 'sqlite3', "~> 1.3.13"
+  spec.add_development_dependency 'sqlite3', "~> 1.4.2"
   spec.add_development_dependency 'yard'
 end
diff --git a/lib/crystalball/extensions/git/lib.rb b/lib/crystalball/extensions/git/lib.rb
index 4c45ee9d..f3cdc647 100644
--- a/lib/crystalball/extensions/git/lib.rb
+++ b/lib/crystalball/extensions/git/lib.rb
@@ -11,8 +11,9 @@ def merge_base(*args)
       opts = args.last.is_a?(Hash) ? args.pop : {}
 
       arg_opts = opts.map { |k, v| "--#{k}" if v }.compact + args
+      command_args = ['merge-base'] + arg_opts.flatten
 
-      command('merge-base', arg_opts)
+      command(*command_args)
     end
   end
 end
diff --git a/lib/crystalball/map_storage/yaml_storage.rb b/lib/crystalball/map_storage/yaml_storage.rb
index 473cc09d..93a24822 100644
--- a/lib/crystalball/map_storage/yaml_storage.rb
+++ b/lib/crystalball/map_storage/yaml_storage.rb
@@ -33,7 +33,7 @@ def read_files(path)
 
           paths.map do |file|
             metadata, *example_groups = file.read.split("---\n").reject(&:empty?).map do |yaml|
-              YAML.safe_load(yaml, [Symbol])
+              YAML.safe_load(yaml, permitted_classes: [Symbol])
             end
             example_groups = example_groups.inject(&:merge!)
 
diff --git a/lib/crystalball/rspec/runner.rb b/lib/crystalball/rspec/runner.rb
index e124f735..920fb74a 100644
--- a/lib/crystalball/rspec/runner.rb
+++ b/lib/crystalball/rspec/runner.rb
@@ -41,7 +41,7 @@ def config
           @config ||= begin
             config_src = if config_file
                            require 'yaml'
-                           YAML.safe_load(config_file.read)
+                           YAML.safe_load(config_file.read, permitted_classes: [Symbol])
                          else
                            {}
                          end
diff --git a/spec/rspec/runner_spec.rb b/spec/rspec/runner_spec.rb
index d5c1c17a..d47670f4 100644
--- a/spec/rspec/runner_spec.rb
+++ b/spec/rspec/runner_spec.rb
@@ -24,7 +24,7 @@
     end
 
     context 'with CRYSTALBALL_CONFIG env variable set' do
-      let(:expected_config) { YAML.safe_load(Pathname('spec/fixtures/crystalball.yml').read) }
+      let(:expected_config) { YAML.safe_load(Pathname('spec/fixtures/crystalball.yml').read, permitted_classes: [Symbol]) }
 
       around do |example|
         ENV['CRYSTALBALL_CONFIG'] = 'spec/fixtures/crystalball.yml'