Redmine

Hello,
i'm a java developer and currently writing a connector between Redmine and an ERP Software. So ruby isn't my strength :>

I am trying to disable email notifications if some choosen user changes a ticket.
Possibly based on a user custom field or a given role.

I started with the plugin tutorial and got that working, but now im searching for the right places to start the real work.

Would be nice if someone could name me some files to look at.

regards
Chris