public function actionMarkSeen()
    {
        if (Thread::podiumMarkAllSeen()) {
            $this->success(Yii::t('podium/flash', 'All unread threads have been marked as seen.'));
            return $this->redirect(['forum/index']);
        }
        $this->error(Yii::t('podium/flash', 'Sorry! There was an error while marking threads as seen. Contact administrator about this problem.'));
        return $this->redirect(['forum/unread-posts']);
    }