public function actionSubscriptions()
    {
        $postData = Yii::$app->request->post();
        if ($postData) {
            if (Subscription::remove(!empty($postData['selection']) ? $postData['selection'] : [])) {
                $this->success(Yii::t('podium/flash', 'Subscription list has been updated.'));
            } else {
                $this->error(Yii::t('podium/flash', 'Sorry! There was an error while unsubscribing the thread list.'));
            }
            return $this->refresh();
        }
        return $this->render('subscriptions', [
            'dataProvider' => (new Subscription())->search(Yii::$app->request->get())
        ]);
    }