public function actionIndex()
    {
        /** @var User */
        $user = Yii::$app->user;
        $subscribedOnly = $user->can('nfy.queue.read.subscribed');
        $queues = [];
        foreach ($this->module->queues as $queueId) {
            /** @var Queue */
            $queue = Yii::$app->get($queueId);
            if (!($queue instanceof components\QueueInterface)
                || ($subscribedOnly
                    && !$queue->isSubscribed($user->getId()))
            ) {
                continue;
            }
            $queues[$queueId] = $queue;
        }

        return $this->render('index', [
            'queues' => $queues,
            'subscribedOnly' => $subscribedOnly,
        ]);
    }