public static function getAppConfig($application, $environment = null, $root_path = null, $locale = null)
 {
     //hook creating app's config and create proxy config over siteConfig
     if ($application == 'site') {
         if ($root_path === null) {
             $root_path = realpath(dirname(__FILE__) . '/..');
         }
         if ($environment === null) {
             $environment = waSystem::getInstance()->getEnv();
         }
         return new mySiteConfig($environment, $root_path, $application, $locale);
     }
     return parent::getAppConfig($application, $environment, $root_path, $locale);
 }