public static function get_by_github_username($github_username) {
	$mysql = bootstrap::get_library('mysql');
	
	$sql   = "SELECT * FROM `login_github` WHERE `github_username` = '%s';";
	$login = $mysql::select('row', $sql, $github_username);
	if (empty($login)) {
		return false;
	}
	
	return new static($login['id']);
}