catarse/catarse — pull request #537 by josemarluedke (2014-01-21 13:55:16+00:00)
Title: Migrate Backer to Contribution

Hello all!

So, here is the migration of Backer to Contribution as we discussed on #501.

All specs are passing and please review it before merging, maybe I forgot something or didn't know about it.

I will open other pull-request for each payment engine when I finish it.