Add a access log for model solutions

app/controllers/solutions_controller.rb

@@ -22,6 +22,8 @@ def show
       end
     end
 
+    ModelSolutionAccessLog.create!(user: current_user, course: @course, exercise_name: @exercise.name)
+
     respond_to do |format|
       format.html
       format.zip do

app/models/model_solution_access_log.rb

@@ -0,0 +1,5 @@
+class ModelSolutionAccessLog < ActiveRecord::Base
+  belongs_to :user
+  belongs_to :course
+end
+

db/migrate/20180903074526_add_model_solution_access_log.rb

@@ -0,0 +1,10 @@
+class AddModelSolutionAccessLog < ActiveRecord::Migration
+  def change
+    create_table :model_solution_access_logs do |t|
+      t.references :user, null: false
+      t.references :course, null: false
+      t.string :exercise_name, null: false
+      t.timestamps
+    end
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20180613083429) do
+ActiveRecord::Schema.define(version: 20180903074526) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -177,6 +177,14 @@
 
   add_index "migrated_submissions", ["from_course_id", "to_course_id", "original_submission_id", "new_submission_id"], name: "unique_values", unique: true, using: :btree
 
+  create_table "model_solution_access_log", force: :cascade do |t|
+    t.integer  "user_id",       null: false
+    t.integer  "course_id",     null: false
+    t.string   "exercise_name", null: false
+    t.datetime "created_at"
+    t.datetime "updated_at"
+  end
+
   create_table "oauth_access_grants", force: :cascade do |t|
     t.integer  "resource_owner_id", null: false
     t.integer  "application_id",    null: false