public function registerServices(DiInterface $di)
    {
        // registering view
        $config = $di->get('config');
        $view = $di->get('view');
        $view->setViewsDir(__DIR__. '/views/');
        $view->setMainView('main');
        $view->setLayoutsDir($config->application->layoutsDir);
        $view->setPartialsDir($config->application->adminPartialDir );
        $view->setLayout('private');
    }