Add Druid (#534)

* Add Druid

README.md

@@ -94,6 +94,7 @@ _Web Analytics_
 
   * [AWStats](http://www.awstats.org/) - Generates web, streaming, ftp or mail server statistics graphically. ([Source Code](https://github.com/eldy/awstats)) `GPLv3` `Perl`
   * [Countly](https://count.ly) - Real time mobile & web analytics, crash reporting and push notifications platform. ([Source Code](https://github.com/countly)) `AGPL` `Javascript`
+  * [Druid](http://druid.io/) - A distributed, column-oriented, real-time analytics data store. ([Source Code](https://github.com/druid-io/druid/)) `Apache` `Java`
   * [GoAccess](http://goaccess.io/) - Real-time web log analyzer and interactive viewer that runs in a terminal. ([Source Code](https://github.com/allinurl/goaccess)) `GPLv2` `C`
   * [Open Web Analytics](http://www.openwebanalytics.com/) - Google Analytics and Piwik alternative. ([Source Code](https://github.com/padams/Open-Web-Analytics/)) `GPL` `PHP`
   * [Piwik](https://piwik.org/) - Leading open-source analytics platform that gives you more than just powerful analytics. ([Source Code](https://github.com/piwik/)) `GPLv3` `PHP`