Ways to put online API documentation using rails

Hey mates!

Currently I am building server data storage for mobile application with
can be accessed via rest API.

I am looking for some kind or ready2go software, which allows to produce
documentation in https://parse.com/docs/rest style.

Ideally, I'd like to store documentation in markdown and process it into
HTML.

I already took a look to nanoc. The problem is that I want to embed
documentation inside rails app, not to build stand alone static website
like https://docs.recurly.com/

Any ideas?