I have worked on at least 50 Ruby web projects based on Ruby on Rails, Sinatra and Padrino in the last eight-plus years of my Ruby carrier. I could say there is no web application I have developed that doesn't have a Procfile to manage its processes with a tool like Foreman.

Foreman is a great tool. It is a mature tool that is both functional and stable and used by many. However do not bundle Foreman with your application. This is a rather common mistake done by many Ruby developers. The Foreman Readme file states:

Ruby users should take care not to install foreman in their project's Gemfile. See this wiki article for more details.

The link explains further why it is a bad idea. In short, Foreman is stable and unless there is a security vulnerability it doesn't make sense for them to update the library. By adding Foreman to your Gemfile your application will adopt its dependencies to suit Foreman. This would usually result in downgrades as foreman is not the most up to date library.

Just use gem install foreman and bundle exec when executing commands.