Fix relation between MultipleChoiceOption and FeedbackOption

When a MultipleChoiceOption is created via the API call PUT /mult-choice, a new FeedbackOption is now automatically inserted into the database that links to the same problem as the MultipleChoiceOption.

The response of PUT /mult-choice will now contain an mc_id that shows the ID of the new MultipleChoiceQuestion and a feedback_id with the ID of the new FeedbackOption.

The relation between MultipleChoiceOption and Problem is now removed. A new relation from FeedbackOption to MultipleChoiceOption is created. However, it is still possible to use problem.mc_options with a hybrid attribute that essentially runs a query in the background.

TODO:

• Ensure that if a FeedbackOption is deleted, the related MultipleChoiceOption is also deleted.

Closes #35 (closed) and #36 (closed).

zesje/api/mult_choice.py

@@ -42,6 +42,10 @@ class MultipleChoice(Resource):
         If the parameter id is not present, a new multiple choice question
         will be inserted with the data provided in the request body.
 
+        For each new multiple choice option, a feedback option that links to
+        the same problem as the multiple choice option is inserted into the
+        database.
+
         Parameters
         ----------
             id: The id of the multiple choice option
@@ -61,7 +65,7 @@ class MultipleChoice(Resource):
         mc_type = 'mcq_widget'
 
         if not id:
-            # Insert new feedback option
+            # Insert new empty feedback option that links to the same problem
             new_feedback_option = FeedbackOption(problem_id=problem_id, text='')
             db.session.add(new_feedback_option)
             db.session.commit()