Behind the scenes: How we built Review Apps

What this post added

This post details the iterative development and release of the Review Apps feature across GitLab versions 8.12, 8.13, and 8.14. Key technical contributions include: 1. In 8.12: Allowing specification of environment URLs directly in `.gitlab-ci.yml` and enabling the use of variables within environment names and URLs, enabling dynamic environments. 2. In 8.13: Reusing manual actions to script app deletion/stopping and introducing a new keyword to identify stop jobs, with a corresponding UI change to a stop button. 3. In 8.14: Automatic detection and execution of the stop job when a branch is deleted, and the introduction of a convention for grouping environments into folders based on naming prefixes to manage the environments list.