What is Gitlab CI?
GitLab CI (Continuous Integration) is a feature integrated into GitLab, a web-based DevOps lifecycle tool. It provides a system to automatically build, test, and deploy code changes submitted in repositories hosted on the platform. GitLab CI uses a YAML file (.gitlab-ci.yml) located in the root of the repository to define the workflows or pipelines for automated processes. These pipelines consist of multiple stages with specific jobs that can run sequentially or in parallel, ensuring that every code commit is integrated into the main branch of the codebase properly, facilitating continuous delivery and deployment.
Source: GPT-4 summary of https://docs.gitlab.com/ee/ci/