Ruby on rails 将Shipping与Ruby on Rails集成

在我的购物车中包含装运报价的最佳方法是什么

我的网站的基本流程是

1.) User selects products  
2.) User is shown cart  
3.) repeat 1 and 2 until User wants to pay  
4.) collect user details ( email, address where items will be shipped to )  
5.) make payment via active merchant  
6.) order is submitted to distributor.  

我想插入一个运输信息，这样用户就可以通过活动商户支付其购买+运输费用

1.) User selects products  
2.) User is shown cart  
3.) repeat 1 and 2 until User wants to pay  
4.) collect user details ( email, address where items will be shipped to )  
5.) calculate the cost of shipment, add cost to cart, show to user;
6.) make payment via active merchant  
7.) order is submitted to distributor.

有没有一个宝石或插件，以帮助我在这里，如果没有。。。我怎样才能做到这一点

谢谢你

---

Stefan

查看活动的装运宝石：

它是Shopify的另一个摘录（比如ActiveMerchant）