Summary
And there you have it! Continuous integration can be a great way to more easily manage contributions as you have an automated way that can enforce your standards and make it easier to debug/be notified of any issues that do arise. It can also help automate the deployment process. It is also customizable and flexible enough to handle virtually any use case.
Once again, congratulations on finishing the book! There has been a lot of content within various areas of Crystal that hopefully provided some helpful information that can be put to use on your future projects or, better yet, serve as a reference for some of the more advanced topics.