If you need any special data attached to the Moderation model, you can use the moderation_creating hook.
For example you have a Comment model, and it is moderated. But your visitors are logged in when they post comments, so you want to add the user ID to the moderation.
first create a migration to add user_id into Moderation
rails g migration AddUserIdToModerations user_id:integer
in models/comment.rb, add something like this:
attr_accessor :moderation_user_id moderation_creating do |m| m.user_id = moderation_user_id end
in your controller:
c = Comment.new c.moderation_user_id = current_user.id c.save
This is just an example of how you could do this. You need the attr_accessor because we are passing the user ID from the controller. In the hook you have access to the Moderation model just before it is saved, so you can modify it like any other model.