I ran into some limitations with Terraform and at the time it didn't support Vultr, so I ended up writing my own provisioner. It goes a bit further with setting up DNS records as well and I rolled in some of my own Docker deploy stuff into it; although in retrospect I should have made that a different project.
Pointing this out... I've gotten a bit of basics working with vultr + terraform but it's not the most straightforward. I'm not the author, but an interested observer.
In my searches for vultr + terraform, your project never came up, but there seems to be some overlap or room for collaboration.
