ActiveRecord relationship question

have you looked at acts_as_tree?
http://api.rubyonrails.com/classes/ActiveRecord/Acts/Tree/ClassMethods.html

but got an "uninitialized constant MenuItem" error.

because you haven't defined an actual MenuItem model class and
associated it with the Menu. i've never gone this route, but i think
the has_many :through method in the api docs uses this technique.

It seems like it should be loading the menu_items. Is there a way to do something like
print_r in php to see what is in the variable?

try Marshal.dump( menu )