public function register()
    {
        // Users can specify only the options they actually want to override
        $this->mergeConfigFrom(
            __DIR__.'/../config/cart_manager.php', 'cart_manager'
        );

        // Bind the driver with contract
        $this->app->bind(CartDriver::class, $this->app['config']['cart_manager']['driver']);

        // Bind the cart class
        $this->app->bind(Cart::class, function ($app) {
            return new Cart($app->make(CartDriver::class));
        });
    }