A very basic Rails app setup with the purpose of showing how you can get up and running with Docker quickly.
$ docker-compose up
Now you need to get your databases ready
$ docker-compose exec web bin/setup
Now you can run the tests
$ docker-compose exec web bin/rails test
You should now be able to visit: http:docker_demo.lvh.me:3000/books
Bingo! 😃
You can see there is a Dockerfile.legacy. This produces a slightly bigger image
but allows you to specify an old version of Ruby. In this demo the lowest you can
go down to is 2.2 due to Rails 5 constraints.