Not much detail needed, I believe :)

Wrapping this software up in a Docker container will surely make development, testing and deployment easier. At first glance, three containers are required: a Redis, a MySQL, and the last one for this app itself.

The Dockerfile would be pretty straightforward: Install necessary software from APT repository and RubyGems, then ENTRYPOINT /usr/src/app/bin/rails. A custom script to initialize the application by reading environment variables and generating the configuration files at the first start is also in need.

With all those stuff ready, a docker-compose.yml should be easy to work out.

The Dockerfile file from Charcoal-SE/metasmoke would be a good point to start at, although it's missing some best-practices for Docker.

Ideas?