git clone https://github.com/rails/rails • % cd rails ; git clone https://github.com/rails/buildkite-config .buildkite/ • % RUBY_IMAGE=rubylang/ruby:master-nightly-bionic docker-compose -f .buildkite/docker-compose.yml build base && CI=1 docker-compose -f .buildkite/docker-compose.yml run default runner actionpack 'rake test'