added LXD to containers below LXC, thanks @boardstretcher

README.md

@@ -554,6 +554,7 @@ Comparison of NoSQL servers: http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-v
   * [Docker](http://www.docker.com/) - Platform for developers and sysadmins to build, ship, and run distributed applications.
     * [Docker Compose](https://docs.docker.com/compose/) - Define and run multi-container Docker applications.
   * [LXC](https://linuxcontainers.org/lxc/) - Userspace interface for the Linux kernel containment features.
+    * [LXD](https://linuxcontainers.org/lxd/) – a container "hypervisor" and a better UX for LXC.
   * [OpenVZ](http://openvz.org) - Container-based virtualization for Linux.