async_request 0.0.4

At [Wolox](http://www.wolox.com.ar) we build Rails Apps. Some of them need heavy computing when a request is received. In order to make the App scalable, we perform those heavy actions in background. We return a job-id and the client asks for it's state a few seconds after. `async_request` gives us the possibility of handling these type of requests in a simple way.