add goreportcard badge

README.md

@@ -1,5 +1,8 @@
 # WeChat SDK for Go
-[![Build Status](https://travis-ci.org/silenceper/wechat.svg?branch=master)](https://travis-ci.org/silenceper/wechat) [![GoDoc](http://godoc.org/github.com/silenceper/wechat?status.svg)](http://godoc.org/github.com/silenceper/wechat)
+[![Build Status](https://travis-ci.org/silenceper/wechat.svg?branch=master)](https://travis-ci.org/silenceper/wechat) 
+[![Go Report Card](https://goreportcard.com/badge/github.com/silenceper/wechat)](https://goreportcard.com/report/github.com/silenceper/wechat)
+[![GoDoc]
+(http://godoc.org/github.com/silenceper/wechat?status.svg)](http://godoc.org/github.com/silenceper/wechat) 
 
 
 使用Golang开发的微信SDK，简单、易用。