Support GitLab CI/CD Configuration

[oxr463]

• The configuration file, .gitlab-ci.yml, is also yaml, but I'm not sure how different they are.

• GitLab CI/CD is also open source! But the code-base is Ruby. I prefer Buildbot since it's written in Python.

• Not sure if GitLab CI/CD can exist without a GitLab instance. Buildbot can be spun up and ran regardless of where your code is kept.

See also: #83