[docs] Add a "Reviewed by Hound" badge (#98)

README.md

@@ -1,6 +1,6 @@
 # gorilla/csrf
 
-[![GoDoc](https://godoc.org/github.com/gorilla/csrf?status.svg)](https://godoc.org/github.com/gorilla/csrf) [![Build Status](https://travis-ci.org/gorilla/csrf.svg?branch=master)](https://travis-ci.org/gorilla/csrf) [![Sourcegraph](https://sourcegraph.com/github.com/gorilla/csrf/-/badge.svg)](https://sourcegraph.com/github.com/gorilla/csrf?badge)
+[![GoDoc](https://godoc.org/github.com/gorilla/csrf?status.svg)](https://godoc.org/github.com/gorilla/csrf) [![Build Status](https://travis-ci.org/gorilla/csrf.svg?branch=master)](https://travis-ci.org/gorilla/csrf) [![Sourcegraph](https://sourcegraph.com/github.com/gorilla/csrf/-/badge.svg)](https://sourcegraph.com/github.com/gorilla/csrf?badge) [![Reviewed by Hound](https://img.shields.io/badge/Reviewed_by-Hound-8E64B0.svg)](https://houndci.com)
 
 gorilla/csrf is a HTTP middleware library that provides [cross-site request
 forgery](http://blog.codinghorror.com/preventing-csrf-and-xsrf-attacks/) (CSRF)