public function register()
    {
        parent::register();

        if (class_exists('Laravel\Lumen\Application') && !defined('SOCIALITEPROVIDERS_STATELESS')) {
            define('SOCIALITEPROVIDERS_STATELESS', true);
        }

        $this->app->singleton(ConfigRetrieverInterface::class, function () {
            return new ConfigRetriever();
        });
    }