IffGit has a new shared runner for building Docker images in GitLab CI. Visit https://iffgit.fz-juelich.de/examples/ci-docker-in-docker for more details.

Tags give the ability to mark specific points in history as being important
Repository has no tags yet.
Use git tag command to add a new one:
git tag -a v1.4 -m 'version 1.4'