Support for AddOn Usages (not really the issue)

[ordo-viddler]

Hi there.

This is rather question than issue (github does not allow to send messages). I found that there's no support for subscription add on usages (https://dev.recurly.com/docs/usage-record-object). Because of that I created one in my branch and here's the question: would you be interested in pulling it into project, or maybe you are already working on solution? Thanks in advance for response!

Wojtek

[cristiangraz]

@ordo-viddler I'm not working on this feature currently—a PR would be great!