I've been able to use anvil with great results for updating existing Heroku apps but am encountering a process state problem when using it as the means for the first deploy against a new app. In particular, even after the first code deploy via anvil the app's web process stays in the "created" state. I've been able to reproduce it in a controlled test case: https://gist.github.com/d171c05c1ddd4f11f64d.
After I do an initial deploy via the usual git push I'm able to use anvil fine.
I think this may be because you do not have a Procfile. Will investigate.
Hello. I apologize for the delayed response. I am currently declaring issue bankruptcy. If this issue still applies to you please feel free to re-open and explain. Thanks :)