/**
	 * @param int $group_id
	 * @param int $user_id
	 * @param int $leader
	 * @param int $pending
	 * @return bool
	 */
	public static function add($group_id, $user_id, $leader = 0, $pending = 0) {
		$sql = 'INSERT INTO ' . self::getFullTableName() . ' (
			group_id,
			user_id,
			group_leader,
			user_pending
		) VALUES (
			:g_id,
			:u_id,
			:g_leader,
			:pending
		)';

		$result = SQL::execute(self::getConnection(), $sql, array("g_id" => $group_id, "u_id" => $user_id, "g_leader" => $leader, "pending" => $pending));

		if($result !== false) {
			// Include libs
			require_once(LIB_DIR . DS . 'class.phpbb_account.php');
			// Empty permission for creating new
			phpbb_account::clearUserPerms($user_id);

			// Send PM new Group
			if(SEND_PM_GROUPCHANGE)
				get_phpbb_info::$instance->sendPM(output::newGroupPM($user_id, phpbb_groups::getGroupName($group_id)), SYSTEM_USER, "Willkommen in der Benutzergruppe " . phpbb_groups::getGroupName($group_id), $user_id);

			return true;
		}
		return false;
	}