Hi, author here. You might want to look at the README provided with the project.
Yes, you are limited to Ubuntu. And yes, the script expects to SSH as root to your server.
As to why it expects that: Doing server provisioning as non-root user does nothing but increase provisioning-complexity.
Deploying as root, on the other hand, is just me being lazy. You're free to fork and send me a pull-request which changes that ;)