Include connection errors in exception handling

ref-test/app/tools/test.py

@@ -133,7 +133,7 @@ def redirect_if_started(function):
         id = session.get('id')
         try:
             if request.method == 'GET' and id and Entry.query.filter_by(id=id).first(): return redirect(url_for('quiz._quiz'))
-        except SQLAlchemyError as exception:
+        except (SQLAlchemyError, ConnectionError) as exception:
             write('system.log', f'Database error when checking if test has been started: {exception}')
             return abort(500)
         return function(*args, **kwargs)