public function queryForSort($type, $categories)
    {

        $db = $this->createQueryBuilder('p');

        if($type=='popularne'){
            $db->addOrderBy('p.views', 'DESC');
        } elseif ($type=='najnowsze'){
            $db->addOrderBy('p.id', 'DESC');
        } elseif($type='najciekawsze'){

            $db->addSelect('p.voteUp - p.voteDown as voteResult');
            $db->addOrderBy('voteResult', 'DESC');
        }

        $db
            ->andWhere('p.isDeleted = :isDeleted')
            ->setParameter('isDeleted', false)
            ->andWhere('p.isWaitingRoom = :isWaitingRoom')
            ->setParameter('isWaitingRoom', false);

             return $db->getQuery();
    }