Simplify db lookup for queries by id

app/profile/background_functions.py

@@ -3,7 +3,7 @@ from app.models import User
 
 def delete_user_(app, user_id):
     with app.app_context():
-        user = User.query.filter_by(id=user_id).first()
+        user = User.query.get(user_id)
         if user is None:
             raise Exception('User {} not found!'.format(user_id))
         user.delete()