Added Judge0 API (#1156)

* Added Judge0 API

* Removed demo link for Judge0 API

README.md

@@ -1062,6 +1062,7 @@ See **[Ticketing](#ticketing)**
   * [Eclipse Che](http://www.eclipse.org/che/) - Open source workspace server and cloud IDE. ([Source Code](https://github.com/eclipse/che)) `EPLv1` `Docker/Java`
   * [ICEcoder](https://icecoder.net/) - ICEcoder is a web IDE / browser based code editor, which allows you to develop websites directly within the web browser. ([Demo](http://demo.icecoder.net/ICEcoder/), [Source Code](https://github.com/mattpass/ICEcoder)) `MIT` `PHP`
   * [JS Bin](http://jsbin.com/) - Open source collaborative web development debugging tool. ([Source Code](https://github.com/jsbin/jsbin)) `MIT` `Nodejs`
+  * [Judge0 API](https://api.judge0.com) - Open source API to compile and run source code. ([Source Code](https://github.com/judge0/api)) `GPLv3` `Ruby`
   * [Koding](http://www.koding.com/) - The simplest way to manage your entire Dev Infrastructure. ([Source Code](https://github.com/koding/koding)) `Apache` `Nodejs`
   * [Microglark](http://micro.glark.io) - A hacky minimalistic remote pair programming editor. ([Demo](http://micro.glark.io), [Source Code](https://github.com/Bluefinch/microglark)) `AGPLv3` `Nodejs`
   * [Regexr](http://regexr.com/) - RegExr is a HTML/JS based tool for creating, testing, and learning about Regular Expressions. ([Source Code](https://github.com/gskinner/regexr/)) `MIT` `Nodejs`