Moving infrastructure updates to the CI pipeline

Remember how we started this book with a discussion of infrastructure as code concepts? Well, if we want to go further treating infrastructure as a real code, then we could (and even should) apply all the same best practices currently existing in software development, and Continuous Integration is a big part of it. The idea behind CI (in case you missed all the buzz about it a few years ago) is to be able to test, build, and deploy your code regularly and automatically. The way it works is by using special software that takes care of all the tasks of making your software ready for production. You only need to define which tasks exactly are part of your CI and how to execute them.

Do you remember that we chose GitLab over GitHub due to some features that GitHub lacks? The most important feature that GitLab has completely integrated into all development workflows and that GitHub doesn't have at all, is GitLab CI. Yes, you can use Travis CI or...