Dynamic Meta data

What is the best way to have a table that defines what the thing is
and another table that defines if you hae it or not.. maybe a table
will describe what i want better!! :

           ----------------define the items in one table
[_] ITEM2
[_] ITEM3

  ^------------------------Define if the user has it in another

Is this polymorphic? please point me where to learn how to do this
the right way..

This is a simple many-to-many relationship.

See here: http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html