I'm trying to get my head around `inverse_of` and I do not get it. 

What does the generated sql look like, if any?

Does the `inverse_of` option exhibit the same behavior if used with `:has_many`, `:belongs_to`, and `:has_many_and_belongs_to`?

Sorry if this is such a basic question.

I saw this example:

```
class Player < ActiveRecord::Base
  has_many :cards, :inverse_of => :player
end

class Card < ActiveRecord::Base
  belongs_to :player, :inverse_of => :cards
end

```