basket update

http/basket.go

@@ -11,6 +11,8 @@ type GetBasketResponse struct {
 	State     string        `json:"state"`
 	CreatedAt time.Duration `json:"created_at"`
 	UpdatedAt time.Duration `json:"updated_at"`
+
+	Error string `json:"error"`
 }
 
 type GetBasketItemsRequest struct {