Hey @Joás Garcia de Melo I'm actually the guy who wrote the Gradle plugin and the library that backed it. Last time I tested it was before that article was written. I always wanted to get back to that project and expand on it. It just a matter forcing myself to make time, which unfortunately I haven't been too successful at.
The Gradle plugin is just a wrapper that gives you defaults and applies the library, it would definitely need to be upgraded to whatever Grails version you might want to use it with. Also the library would have to have it's groovy version updated and re compiled with that version. Alternatively the library could be added without the Gradle plugin, provided you put the proper configuration in place.