Add integration with Circle CI, drone.io and codeship.

Author: javadev

README.md

@@ -4,6 +4,9 @@ underscore-java
 [![Maven Central](https://img.shields.io/maven-central/v/com.github.javadev/underscore.svg)](http://search.maven.org/#search%7Cga%7C1%7Cg%3A%22com.github.javadev%22%20AND%20a%3A%22underscore%22)
 [![Build Status](https://secure.travis-ci.org/javadev/underscore-java.png)](https://travis-ci.org/javadev/underscore-java)
 [![Coverage Status](https://coveralls.io/repos/javadev/underscore-java/badge.png?branch=master)](https://coveralls.io/r/javadev/underscore-java)
+[![Circle CI](https://circleci.com/gh/javadev/underscore-java.png?style=badge)](https://circleci.com/gh/javadev/underscore-java)
+[![Build Status](https://drone.io/github.com/javadev/underscore-java/status.png)](https://drone.io/github.com/javadev/underscore-java/latest)
+[![Codeship Status for javadev/underscore-java](https://codeship.com/projects/c989fef0-f3ab-0132-7ca5-16cf317d1634/status?branch=master)](https://codeship.com/projects/85467)
 
 Requirements
 ============