Reactivecocoa 是个好东西，但是学起来还是花了不少精力。
首先推荐这篇文章决对干货
http://limboy.me/ios/2014/01/05/ios-rest-client-implementation.html
BNR 的这个例子可以帮助入门
https://www.bignerdranch.com/blog/data-driven-ios-development-reactive…
视频详细讲解
http://www.raywenderlich.com/74131/mvvm-tutorial-with-reactivecocoa-pa…
API model层封装,用了AFNetworking Mantle
https://github.com/instructure/canvaskit
