public function actionIndex()
    {
        $userId = Yii::$app->getUser()->getId();
        $query = (new Query())
            ->from('{{%notifications}}')
            ->andWhere(['or', 'user_id = 0', 'user_id = :user_id'], [':user_id' => $userId]);

        $pagination = new Pagination([
            'pageSize' => 20,
            'totalCount' => $query->count(),
        ]);

        $list = $query
            ->orderBy(['id' => SORT_DESC])
            ->offset($pagination->offset)
            ->limit($pagination->limit)
            ->all();

        $notifs = $this->prepareNotifications($list);

        return $this->render('index', [
            'notifications' => $notifs,
            'pagination' => $pagination,
        ]);
    }