Ensure quick start guide is actually working
We need to check that https://docs.gitlab.com/ce/topics/autodevops/quick_start_guide.html is actually working.
There are probably some changes to do, as reported on Slack:
- it is not possible to run the first pipeline with the button (we don't have
.gitlab-ci.yml), so mention first push or other means to run it - example app should be https://gitlab.com/auto-devops-examples/minimal-ruby-app to make buildpacks working correctly