Add go reportcard

README.md

@@ -1,7 +1,7 @@
 # RxGo
 
 [![Join the chat at https://gitter.im/reactivex-go/Lobby](https://badges.gitter.im/reactivex-go/Lobby.svg)](https://gitter.im/reactivex-go/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
-[![Build Status](https://travis-ci.org/ReactiveX/RxGo.svg?branch=master)](https://travis-ci.org/ReactiveX/RxGo)    [![Coverage Status](https://coveralls.io/repos/github/jochasinga/RxGo/badge.svg?branch=master)](https://coveralls.io/github/jochasinga/RxGo?branch=master)    
+[![Build Status](https://travis-ci.org/ReactiveX/RxGo.svg?branch=master)](https://travis-ci.org/ReactiveX/RxGo)    [![Coverage Status](https://coveralls.io/repos/github/jochasinga/RxGo/badge.svg?branch=master)](https://coveralls.io/github/jochasinga/RxGo?branch=master) [![Go Report Card](https://goreportcard.com/badge/github.com/reactivex/rxgo)](https://goreportcard.com/report/github.com/reactivex/rxgo)    
 Reactive Extensions for the Go Language
 
 ## Call for Maintainers