Try to automate Docker builds

[php-coder]

• read https://docs.docker.com/docker-hub/builds/
• read https://docs.docker.com/docker-hub/builds/automated-testing/
• read https://docs.docker.com/docker-hub/builds/advanced/
• read https://docs.docker.com/docker-hub/builds/link-source/
• read https://docs.docker.com/docker-hub/builds/classic/

Bonus: Dockerfile will be visible on dockerhub.