Engines Plugin Breaks Rails Exception Notifier No More

Courtesy of one Mr. Andrew Roth (via the Engines mailing list, helpful guys there), here is how to fix errors between Exception Notifier and the Engines plugin:

It was easily fixed by making the exception_notifier an engine by making use
of an app folder to play nice with engines (or should we say so engines
would play nice with it).

So a find|grep -v svn in my vendor/plugins/exception_notification folder
gives

./app
./app/helpers
./app/helpers/exception_notifier_helper.rb
./app/models
./app/models/exception_notifier.rb
./app/views
./app/views/exception_notifier
./app/views/exception_notifier/exception_notification.rhtml
./app/views/exception_notifier/_backtrace.rhtml
./app/views/exception_notifier/_environment.rhtml
./app/views/exception_notifier/_inspect_model.rhtml
./app/views/exception_notifier/_request.rhtml
./app/views/exception_notifier/_session.rhtml
./app/views/exception_notifier/_title.rhtml
./init.rb
./lib
./lib/exception_notifiable.rb
./README
./test
./test/exception_notifier_helper_test.rb
./test/test_helper.rb

and cat init.rb is just

require "action_mailer"