About a month ago one of our development teams is fortunate enough to have the chance implementing ServiceMerchant plugin
It is a plugin that makes use of ActiveMerchant, but designed specifically for recurring billing / subscription payment requirement.

As with all other gems, the best way to understand a gem, besides asking shifu Google, is to dig into the gem code itself and find sample apps, example usage, test units, etc

It’s pretty straightforward, and yet I feel like wanting to share some interesting things: