public function categoryValidator($attr)
 {
     if (!$this->hasErrors($attr)) {
         $category = Category::find()->active()->forUsersInSameGroup($this->_user)->andWhere(['id' => $this->{$attr}])->all();
         if (!$category) {
             $this->addError($attr, 'There is no such parent category');
             return false;
         }
         return true;
     }
 }
 public function actionIndex()
 {
     $categories = Category::find()->active()->forUsersInSameGroup($this->_user)->expand(Yii::$app->request->getQueryParams())->asArray()->all();
     return ['status' => true, 'data' => $categories];
 }