Update README.md

Add Tsuru, Tsuru is an extensible and open source Platform as a Service software

README.md

@@ -119,6 +119,7 @@
 * [OpenNebula](http://opennebula.org/) - An user-driven cloud management platform for sysadmins and devops.
 * [OpenStack](https://www.openstack.org/) - Open source software for building private and public clouds.
 * [The Foreman](http://theforeman.org/) - Foreman is a complete lifecycle management tool for physical and virtual servers. FOSS.
+* [Tsuru](https://tsuru.io) - Tsuru is an extensible and open source Platform as a Service software.
 
 ## Cloud Orchestration