public function getListConcurrent($id_tournoi)
 {
     $q = $this->_db->query('SELECT id_concurrent, id_tournoi, nom_concurrent, nb_concurrent FROM concurrent WHERE id_tournoi = ' . $id_tournoi . ' ORDER BY id_concurrent');
     while ($donnees = $q->fetch(PDO::FETCH_ASSOC)) {
         $concurrent = new Concurrent();
         $concurrent->hydrate($donnees);
         $tab_concurrent[] = $concurrent;
     }
     return $tab_concurrent;
 }