/**
  * Deletes an existing Clients model.
  * If deletion is successful, the browser will be redirected to the 'index' page.
  * @param string $id
  * @return mixed
  */
 public function actionDelete($id)
 {
     if ($this->findModel($id)->delete()) {
         Tasks::deleteAll('client = :client', [':client' => $id]);
         Contacts::deleteAll('client = :client', [':client' => $id]);
     }
     return $this->redirect(['index']);
 }