Write a Vagrantfile (Vagrant, Virtualbox)

I'd like to create a VirtualBox virtual machine using a Vagrantfile and Vagrant. The virtual machine should have Ubuntu 16.04 LTS (using one of the base boxes, e.g. [login to view URL]) with full network access, and when run should open the Ubuntu desktop GUI. It should also have Docker installed (done via a provisioning bash command, e.g. sudo apt-get install docker-engine). I think this is reasonably straightforward for somebody that knows what they are doing, I'm just struggling a bit with the configuration. If any of the above is unclear, please let me know. Please only bid if you have experience with Vagrant - this should be a case of writing a quick script for somebody that knows what they are doing. Unfortunately Vagrant was not available in the list of required skills.