public function register()
    {

        $this->app->singleton(
            ShopifyContract::class, function($app) {

             $shopifyAuth = new ShopifyAuth($app['request'], config( 'shopify.key' ),
                                config( 'shopify.secret' ), config( 'shopify.redirectURL' ));

             return new Shopify($shopifyAuth);

        });
    }