public function actionQuiz($id)
 {
     $quiz = new Quiz();
     $quiz->id = $id;
     if (Yii::$app->request->post()) {
         return $this->render('single_quiz', ['quizQuestion' => $quiz->getQuiz($id), 'result' => $quiz->getQuizResult(array_sum(Yii::$app->request->post('answers')))]);
     }
     return $this->render('single_quiz', ['quizQuestion' => $quiz->getQuiz($id)]);
 }