Thanks to some advice from the list earlier, I now have a Permission model that links User and Thing (using has_many and :through). I can easily get the list of current users by doing the following: @thing = Thing.find(params[:id]) @current_users = @thing.users But in my view, I want to construct a select of those users that haven't had permissions added, so they can be added. I've tried some pretty stupid stuff like subtracting @thing.users from User.find :all, but this doesn't seem to work. What is the easiest way of picking out all users that aren't currently associated with the given thing? Then, I'll create a multi-select and try to work out how to iterate through all the selected ones and add their permissions. Thanks.
on 2006-04-19 13:01