readme: added downloads badge

Author: mmatczuk

README.md

@@ -1,4 +1,4 @@
-# Tunnel [![GoDoc](http://img.shields.io/badge/go-documentation-blue.svg?style=flat-square)](http://godoc.org/github.com/mmatczuk/go-http-tunnel) [![Go Report Card](https://goreportcard.com/badge/github.com/mmatczuk/go-http-tunnel)](https://goreportcard.com/report/github.com/mmatczuk/go-http-tunnel) [![Build Status](http://img.shields.io/travis/mmatczuk/go-http-tunnel.svg?style=flat-square)](https://travis-ci.org/mmatczuk/go-http-tunnel.svg?branch=master)
+# Tunnel [![GoDoc](http://img.shields.io/badge/go-documentation-blue.svg?style=flat-square)](http://godoc.org/github.com/mmatczuk/go-http-tunnel) [![Go Report Card](https://goreportcard.com/badge/github.com/mmatczuk/go-http-tunnel)](https://goreportcard.com/report/github.com/mmatczuk/go-http-tunnel) [![Build Status](http://img.shields.io/travis/mmatczuk/go-http-tunnel.svg?style=flat-square)](https://travis-ci.org/mmatczuk/go-http-tunnel.svg?branch=master) [![Github All Releases](https://img.shields.io/github/downloads/mmatczuk/go-http-tunnel/total.svg)](https://github.com/mmatczuk/go-http-tunnel/releases)
 
 Tunnel is fast and secure client/server package that enables proxying public connections to your local machine over a tunnel connection from the local machine to the public server. **It enables you to share your localhost when you don't have a public IP or you are hidden by a firewall**.