public function getSubscriptionsCount()
    {
        $cache = Podium::getInstance()->podiumCache->getElement('user.subscriptions', $this->id);
        if ($cache === false) {
            $cache = (new Query)->from(Subscription::tableName())->where([
                    'user_id' => $this->id,
                    'post_seen' => Subscription::POST_NEW
                ])->count();
            Podium::getInstance()->podiumCache->setElement('user.subscriptions', $this->id, $cache);
        }
        return $cache;
    }