Use the same Docker image for multiple process types with heroku.yml

Change effective on 18 July 2018

heroku.yml now allows you to use the same Docker image for multiple process types.

In the following example, heroku.yml builds one Docker image and uses it for both the web and worker process types:

build:
  docker:
    web: Dockerfile
run:
  web: bundle exec puma -C config/puma.rb
  worker:
    command: python myworker.py
    image: web

Learn more about Docker builds with heroku.yml.