public function actionIndex()
{
  $key =Yii::$app->request->post("key");
  $query = Post::find()->joinWith('cate');
  $post = $query->orderBy(['post.id' => SORT_DESC])->asArray()->where(['post.status' => 1]);
  if($key){
    $post->andFilterWhere(['like', 'post.title', $key])
      ->orFilterWhere(['like', 'post.content', $key]);
  }
  $pages = new Pagination([
    'totalCount' => $post->count(),
    'defaultPageSize' => 10
  ]);
  $model = $post->offset($pages->offset)->limit($pages->limit)->all();
  return $this->render('index', [
    'model' => $model,
    'pages' => $pages,
  ]);
}