fix an internal server error in list_all action by removing respond_to block

Author: ptgms

app/controllers/cases_controller.rb

@@ -24,9 +24,7 @@ def list_all
       object << { pointbox: c.determine_pointbox, case: c }
     end
 
-    respond_to do |format|
-      format.json { render json: object }
-    end
+    render json: object
   end
 
   def new