Help with nested forms

When I browse to artist_new_path I do not see the fields from the user
table (in this example: city). Why is this?

class User < ActiveRecord::Base
  has_one :artist
end

Anyone?

class Artist < ActiveRecord::Base

belongs_to :user

accepts_nested_attributes_for :user

this is backwards, artist is nested inside users but you want artist to accept nested attributes of users.

It only works the when you are accepting attributes for the child model from inside the parent.

Ok... someone suggested to use virtual attributes instead. Is this the
right way to go?

Basically a registered user can sign up as an artist.
Artist model has the following fields: id, user_id, band_name
User model has: id, name, city_id, genre_id

In the artist registration form:

<%= form_for(@artist) do |f| %>

  <ul>
    <li class="clearfix">
      <%= f.label :band_name %>
      <%= f.text_field :band_name %>
    </li>

    <li class="clearfix">
      <%= f.label :city_id %>
      <%= f.grouped_collection_select(:city_id,
Country.find(:all), :cities, :name, :id, :name, { :prompt => 'Select a
city' }) %>
    </li>

    <li class="clearfix">
      <%= f.label :genre_id %>
      <%= f.collection_select :genre_id, Genre.all, :id, :name,
{ :prompt => 'Select a genre' } %>
    </li>
  </ul>

<% end %>

In my artist model, I created virtual attributes:

class Artist < ActiveRecord::Base
  belongs_to :user
  has_many :medias

  validates_presence_of :band_name
  attr_accessible :band_name, :city_id, :genre_id

  # Virtual attribute. Needed when user wants to register as an artist
  def city_id

  end

  # Virtual attribute. Needed when user wants to register as an artist
  def genre_id

  end

  def after_create
    # Update the user fields: city_id and genre_id
    self.user.update_attributes(
      :city_id => self.city_id,
      :genre_id => self.genre_id
    )
  end
end

However, when I submit the form, I get:

ActiveRecord::UnknownAttributeError in ArtistsController#create
unknown attribute: city_id

The error occurs in the artist controller def create method. The first
line: @artist = Artist.new(params[:artist])

Am I doing this right? What is wrong?

Basically, all I am trying to do is create an artist (with band_name),
and update the user model based on what values were passed (city_id,
genre_id)