I have a three table construct. A "Users" table. Users have a one-to-
one relationship with a "Carts" table for saving the contents of a
shopping cart to the DB. I have a "Products" table for holding
product information. The Carts have a many-to-many relationship with
the Products. (One cart might have more than one product in it, and
one product might be represented in more than one user's cart.)
What association would be best to describe this relationship? And
what would the migrations and model statements look like?