add Laradock to Development Environment

README.md

 * [Puppet](https://puppet.com/) - A server automation framework and application.
 * [Vagrant](https://www.vagrantup.com/) - A portable development environment utility.
 * [Docker](https://www.docker.com/) - A containerization platform.
+* [Laradock](http://laradock.io/) - A full PHP development environment based on Docker.
 
 ### Virtual Machines
 *Alternative PHP virtual machines.*