public function findByWorkspace(Workspace $workspace, $orderedBy = 'id', $order = 'ASC')
    {
        $dql = "
            SELECT r FROM Claroline\CoreBundle\Entity\Role r
            JOIN r.workspace ws
            WHERE ws.id = :workspaceId
            ORDER BY r.{$orderedBy} {$order}
        ";
        $query = $this->_em->createQuery($dql);
        $query->setParameter('workspaceId', $workspace->getId());

        return $query->getResult();
    }