Collections with visibility

Yeah I thought if a class was defined as

``` ruby
module Owned
  def policy_class
    OwnedObjectPolicy
  end
end

module Visibility
  def policy_class
    OwnedVisibilityPolicy
  end
end

class Thingy < ActiveRecord::Base
  include Owned
  include Visibility
end

Thing.new.policy_class == OwnedVisibilityPolicy.
```