public function findGroupByName($name, $executeQuery = true)
    {
        $dql = '
            SELECT g
            FROM Claroline\CoreBundle\Entity\Group g
            WHERE g.name = :name
        ';

        $query = $this->_em->createQuery($dql);
        $query->setParameter('name', $name);

        return $executeQuery ? $query->getOneOrNullResult() : $query;
    }