@ColinHarrington shows you, in this Grails Guide, how to include GIT commit info to your Grails application. An effortless way to add traceability to your project!
Gradle is Grails 3 build system. And that it is a big deal. You can use many libraries directly without the need of a plugin.
Didin Jamaludin show you how to use Apache POI to work with Excel files.
If you write a Grails Web application chances are you are going to need to send transactional emails; password reset, welcome emails, notifications. Didin Jamaludin show you how to send emails from Grails in this blog post.