public function actionCollected()
 {
     if (Yii::$app->request->get('rejected')) {
         return $this->render('collected_failed');
     }
     $collection = new Collection();
     $collection->login = Yii::$app->getSession()->get('collection.login');
     $collection->is_fulfilled = true;
     $collection->sum = Collection::calculateSum();
     $collection->save();
     return $this->render('collected');
 }