add diagram, add coverage badge

Author: edtoken

README.md

@@ -28,6 +28,7 @@ ActionCreator + ActionSelector, reducers are created automatically
 [![Build Status](https://api.travis-ci.org/edtoken/redux-tide.svg?branch=master)](https://travis-ci.org/edtoken/redux-tide)
 [![Maintainability](https://api.codeclimate.com/v1/badges/5952e9edfa038e49658f/maintainability)](https://codeclimate.com/github/edtoken/redux-tide/maintainability)
 [![npm downloads](https://img.shields.io/npm/dm/redux-tide.svg?style=flat-square)](https://www.npmjs.com/package/redux-tide)
+[![Coverage Status](https://coveralls.io/repos/github/edtoken/redux-tide/badge.svg?branch=master)](https://coveralls.io/github/edtoken/redux-tide?branch=master)
 [![Inline docs](https://inch-ci.org/github/edtoken/redux-tide.svg?branch=master)](https://inch-ci.org/github/edtoken/redux-tide)
 [![HitCount](http://hits.dwyl.com/edtoken/redux-tide.svg)](http://hits.dwyl.com/edtoken/redux-tide)