fix issue #89: add patreon link

README.md

@@ -3,10 +3,10 @@
 > Functional mechanism based on context to perform actions repetitively until successful.
 
 [![Awesome](https://cdn.rawgit.com/sindresorhus/awesome/d7305f38d29fed78fa85652e3a63e154dd8e8829/media/badge.svg)](https://github.com/avelino/awesome-go#utilities)
+[![Patreon](https://img.shields.io/badge/patreon-donate-orange.svg)](https://www.patreon.com/octolab)
 [![Build Status](https://travis-ci.org/kamilsk/retry.svg?branch=master)](https://travis-ci.org/kamilsk/retry)
-[![Coverage Status](https://coveralls.io/repos/github/kamilsk/retry/badge.svg)](https://coveralls.io/github/kamilsk/retry)
 [![Go Report Card](https://goreportcard.com/badge/github.com/kamilsk/retry)](https://goreportcard.com/report/github.com/kamilsk/retry)
-[![Exago](https://api.exago.io/badge/rank/github.com/kamilsk/retry)](https://www.exago.io/project/github.com/kamilsk/retry)
+[![Coverage Status](https://coveralls.io/repos/github/kamilsk/retry/badge.svg)](https://coveralls.io/github/kamilsk/retry)
 [![GoDoc](https://godoc.org/github.com/kamilsk/retry?status.svg)](https://godoc.org/github.com/kamilsk/retry)
 [![License](https://img.shields.io/github/license/mashape/apistatus.svg?maxAge=2592000)](LICENSE)