public function actionAdd()
 {
     $model = new Leaveword();
     if ($model->load(\Yii::$app->request->post())) {
         $model->leave_time = time();
         $model->leave_uid = \Yii::$app->session['userid'];
         if ($model->validate() && $model->save()) {
             \Yii::$app->getSession()->setFlash('success', '留言成功!^_^');
             $this->redirect(['leaveword-admin/index']);
         }
     }
     $admins = Admin::findBySql('SELECT id,username FROM tbl_admin')->asArray()->all();
     $admin_map[0] = '所有人';
     foreach ($admins as $admin) {
         $admin_map[$admin['id']] = $admin['username'];
     }
     unset($admin_map[\Yii::$app->session['userid']]);
     // var_dump($admin_map);exit();
     return $this->render('add', ['model' => $model, 'admin_map' => $admin_map]);
 }