## UserController
 def new
    @user = User.new
    @artist = Artist.new
  end

  def create
    logout_keeping_session!
    @user = User.new(params[:user])
    @artist = @user.build_artist(params[:artist])
    @user.register! if @user && @user.valid?
    success = @user && @user.valid?
    if success && @user.errors.empty?
            redirect_back_or_default('/')
      flash[:notice] = "Thanks for signing up!  We're sending you an email with your activation code."
    else
      flash[:error]  = "We couldn't set up that account, sorry.  Please try again, or contact an admin (link is above)."
      render :action => 'new'
    end
  end

## User model

class User < ActiveRecord::Base
  has_one :artist

  validate do |user|
    user.validate_artist
  end

  def validate_artist
    unless artist.valid?
      artist.errors.each_full { |msg| errors.add(:artist, "is invalid: #{msg}") }
    end
  end

  # ...
end

## Artist Model

class Artist < ActiveRecord::Base
  validates_presence_of     :name
  validates_uniqueness_of   :name,    :case_sensitive => false
end



## User:View:New

<h1>Sign up as a new user</h1>
<% @user.password = @user.password_confirmation = nil %>

<%= error_messages_for :user %>
<% form_for :user, :url => users_path do |f| -%>
<p><label for="email">Email (this will be your login name)</label><br/>
<%= f.text_field :email %></p>

<p><label for="name">Artist Name</label><br/>
<% fields_for "artist", @artist do |a| %>
  <%= a.text_field :name %>
<% end %>
<p><label for="password">Password</label><br/>
<%= f.password_field :password %></p>

<p><label for="password_confirmation">Confirm Password</label><br/>
<%= f.password_field :password_confirmation %></p>

<p><%= submit_tag 'Sign up' %></p>
<% end -%>