public static function get($request, $match)
    {
        $group = Pluf_Shortcuts_GetObjectOr404('User_Group', $match['group_id']);
        $role = new User_Role();
        $roles = $role->getList(array(
            'view' => 'join_group',
            'filter' => array(
                'user_group_id=' . $group->id
            )
        ));
        if ($roles->count() == 0) {
            throw new Pluf_Exception_DoesNotExist('Group has not such role');
        }
        return $roles[0];
    }