Описание тега procfile
The Procfile is a simple YAML-esque file which sits in the root of your application code and is pushed to your application when you deploy.
The Procfile is a simple YAML-esque file which sits in the root of your application code and is pushed to your application when you deploy. This file contains a definition of every process you require in your application, and how that process should be started. It is intended to be consumed by Foreman, a utility written by a Heroku Engineer.
Most questions that need this tag will benefit from the heroku tag.