Distinguish between intermediate and final feedback

* Also add more information to user_exercise_feedback
* Migrate existing feedback to enrich with submissions

db/migrate/20201019090123_add_normalized_score_and_submission_to_user_exercise_feedback.rb

@@ -0,0 +1,23 @@
+class AddNormalizedScoreAndSubmissionToUserExerciseFeedback < ActiveRecord::Migration[5.2]
+  def change
+    add_column :user_exercise_feedbacks, :normalized_score, :float
+    add_reference :user_exercise_feedbacks, :submission, foreign_key: true
+
+    # Disable automatic timestamp modification
+    ActiveRecord::Base.record_timestamps = false
+    UserExerciseFeedback.all.find_each do |uef|
+      latest_submission = Submission
+                          .where(user_id: uef.user_id, user_type: uef.user_type, exercise_id: uef.exercise_id)
+                          .where('created_at < ?', uef.updated_at)
+                          .order(created_at: :desc).first
+
+      # In the beginning, CodeOcean allowed feedback for exercises while viewing an RfC. As a RfC
+      # might be opened by any registered learner, feedback for exercises was created by learners
+      # without having any submission for this particular exercise.
+      next if latest_submission.nil?
+
+      uef.update(submission: latest_submission, normalized_score: latest_submission.normalized_score)
+    end
+    ActiveRecord::Base.record_timestamps = true
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2020_10_07_104221) do
+ActiveRecord::Schema.define(version: 2020_10_19_090123) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -423,6 +423,9 @@ ActiveRecord::Schema.define(version: 2020_10_07_104221) do
     t.integer "user_estimated_worktime"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.float "normalized_score"
+    t.bigint "submission_id"
+    t.index ["submission_id"], name: "index_user_exercise_feedbacks_on_submission_id"
   end
 
   create_table "user_exercise_interventions", id: :serial, force: :cascade do |t|
@@ -455,4 +458,5 @@ ActiveRecord::Schema.define(version: 2020_10_07_104221) do
   add_foreign_key "request_for_comments", "submissions", name: "request_for_comments_submissions_id_fk"
   add_foreign_key "submissions", "study_groups"
   add_foreign_key "tips", "file_types"
+  add_foreign_key "user_exercise_feedbacks", "submissions"
 end