Using minimal image with docker-compose 3

Docker with docker-compose 3.6 using:

• Oficial version's images to containers.
• Use container like services.
• Create volumes to use with services.

Docker to Rails using rbenv

Build several containers to run Rails Application, the main features are:

• Build an own Dockerfile for how to work with Docker.
• Working with multiples containers using docker-compose.
• Using links and environment's variables in docker-compose.
• Persist MySQL data in volumes.