public static function registerApp(string $namespace, string $path = null)
    {
        $namespace = rtrim($namespace, '\\');
        if ($path == null) {
            $path = constant('STRAY_PATH_APPS') . str_replace(
                '_',
                DIRECTORY_SEPARATOR,
                str_replace('\\', DIRECTORY_SEPARATOR, $namespace)
            );
        }
        self::$namespaces[$namespace] = $path;
        self::$applications[] = $namespace;
    }