Update README.md

Author: chzyer

README.md

@@ -2,7 +2,7 @@ Logex
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 [![Build Status](https://travis-ci.org/go-logex/logex.svg?branch=master)](https://travis-ci.org/go-logex/logex)
 [![GoDoc](https://godoc.org/gopkg.in/logex.v1?status.svg)](https://godoc.org/gopkg.in/logex.v1)
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+[![Join the chat at https://gitter.im/go-logex/logex](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/go-logex/logex?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 
 An golang log lib, supports tracing and level, wrap by standard log lib