Delegates and building associations

Class User << ActiveRecord::Base
  has_one :profile
  delgate :description, :description=, :to => :profile

end

I'd like to do,

@user = User.create(:name => 'Foo Bar', :description => 'Slow.')
or
@user = User.update_attributes(:description => 'Slow')

and have AR create/update the profile model and association (if it
doesn't already exist).

How can I do this? Ideally this would be handled in User's
initialize, or callback, but I can't get anything to work. When
reaching the delegate statement I get an error that profile is nil.

Thanks

Write Something like this in your user model
before_create :build_profile_for_this_user

def build_proile_for_this_user
    build_profile
  end