Fix sorting in /videos/<id>/comments API endpoint

comments-api/app.py

@@ -151,7 +151,9 @@ class CommentsResource(flask_restful.Resource):
         if args['sort_order'] == 'random':
             q = q.order_by(sqlalchemy.func.random())
         elif args['sort_by']:
-            col = getattr(Comment, args['sort_by'], None)
+            col = getattr(Association, args['sort_by'], None)
+            if not col:
+                col = getattr(Comment, args['sort_by'], None)
             if col:
                 if args['sort_order']:
                     order_by = getattr(col, args['sort_order'], None)