A new, empty Rails project (created with `rails new api-demo`).
Tweaked settings in the project to match our team's usual set up:

- Locked the version of Ruby to 2.1.2.
- Changed the testing framework.
- Set up a Vagrantfile and VM provisioning script (for use with Vagrant).
- Updated .gitignore to ignore the files/folders created by Vagrant.
Set up access to the PayTrace API from any Controller class in the app.
Added a cart controller with checkout and pay actions.
Added a full README.md.