Continuous integration: From Jenkins to GitLab using Docker

What this post added

This post details the migration of a Jenkins CI job to GitLab CI, specifically highlighting the use of Docker to manage dependencies and external services. It contrasts the verbose and machine-dependent configuration of Jenkins with the streamlined `.gitlab-ci.yml` approach enabled by Docker. Key technical contributions include: defining a custom Docker image for PHP dependencies, using Docker services to orchestrate MongoDB, and simplifying test execution by isolating the environment. The post also demonstrates how to run GitLab CI jobs locally using GitLab Runner.