Build a Ruby development environment in Docker container.
Following tools are preinstalled:
- zsh: the shell
 - vim: default editor
 - silversearcher-ag: faster grep
 - curl: to download or test APIs
 - traefik: reverse proxy for apps built in the container
 - locales: setup UTF-8
 - sudo: enable /etc/sudoers
 - headless chrome for automatic testing
 
docker-compose up -d