Docs: add badges

Author: aichbauer

README.md

@@ -2,6 +2,10 @@
 
 > Check if a git remote repository exists
 
+[![Build Status](https://travis-ci.org/aichbauer/node-is-git-remote.svg?branch=master)](https://travis-ci.org/aichbauer/node-is-git-remote)
+[![Build status](https://ci.appveyor.com/api/projects/status/eatqdfs3a7uhniti?svg=true)](https://ci.appveyor.com/project/aichbauer/node-is-git-remote)
+[![Coverage Status](https://coveralls.io/repos/github/aichbauer/node-is-git-remote/badge.svg?branch=master)](https://coveralls.io/github/aichbauer/node-is-git-remote?branch=master)
+
 ## Installation
 
 ```sh