Debugging Grails 3 in Intellij 2016

I got stuck trying to edit run/debug configuration in Intellij to get my Grails project to debug. There where lots of posts about forks etc, etc.
But it is much simpler than that.

Just go to

grails-app/init/webtracker.api/Application

and right click on Application and select Debug 'Application.main()'

There we go
Intellij will remember these and you can get to them quick in the Build menu