public function up()
 {
     foreach (\app\modules\review\models\Review::findAll(['root_id' => 0]) as $model) {
         $model->root_id = $model->id;
         $model->save();
     }
 }
 /**
  * @param array $returnUrl
  * @return Response
  * @throws \Exception
  */
 public function actionRemoveAll($returnUrl = ['index'])
 {
     $items = Yii::$app->request->post('items', []);
     if (!empty($items)) {
         $items = Review::findAll(['id' => $items]);
         foreach ($items as $item) {
             $item->delete();
         }
         Yii::$app->session->setFlash('info', Yii::t('app', 'Objects removed'));
     }
     return $this->redirect($returnUrl);
 }