First of all thanks for this project, and congrats for the s/w design :)
I would like to suggest a more "formal" way for the contact list of the notification settings.
Instead of adding email-addresses, to add usernames (like it's done on the Permissions tab of a repository configuration). Then send the email to the mail field of each user.
Also a check-button to enable sending to all users that have permissions would be very useful (instead of adding them again on the notification tab).
I could help to write the changes, but I looked at the notify-plugin, and I don't know how to get the users. Didn't spend much time though.. considering someone here could inform me.
Best regards, Stefanos