I'm working with an old Rails app that was initially built before Bundler and Gemfiles. Is it possible to push this app up to Heroku without a Gemfile? The app is in production on the Bamboo Stack and working without one. I'm trying to add a development environment on the Cedar Stack (Bamboo is now closed) and getting an error:
-----> Heroku receiving push
-----> Removing .DS_Store files
! Heroku push rejected, no Cedar-supported app detected
Is it no longer possible to push to Heroku without a Gemfile?
I'll add a Gemfile if that's what it takes.