Devise nested form issue

new.html.erb

<h2>Sign up</h2>

<%= form_for(resource, :as => resource_name, :url => registration_path(resource_name)) do |f| %>
  <%= devise_error_messages! %>
  <% f.object.build_organization unless f.object.organization %>
  <% f.fields_for :organization do |o| %>

  <p><%= o.label :name %><br/>
  <%= o.text_field :name %></p>

  <% end %>
  <p><%= f.label :email %><br />
  <%= f.email_field :email %></p>

  <p><%= f.label :password %><br />
  <%= f.password_field :password %></p>

  <p><%= f.label :password_confirmation %><br />
  <%= f.password_field :password_confirmation %></p>

  <p><%= f.submit "Sign up" %></p>
<% end %>

<%= render :partial => "devise/shared/links" %>

organization.rb

class Organization < ActiveRecord::Base
  belongs_to :boss, :class_name => 'User', :foreign_key => 'owner_id', :dependent => :destroy
  has_many :listings, :dependent => :destroy
  has_many :peons, :class_name => 'User', :dependent => :destroy
  has_many :exports, :dependent => :destroy
  attr_accessible :name, :owner_id, :phone, :address, :city, :state, :zip, :country, :contact_email, :website, :hashed_id
  after_create :write_hash
.
.
.

page html source

.
.
.
        <h2>Sign up</h2>

      
        <form accept-charset="UTF-8" action="/users" class="user_new" id="user_new" method="post"><div style="margin:0;padding:0;display:inline"><input name="utf8" type="hidden" value="&#x2713;" /><input name="authenticity_token" type="hidden" value="qtJsSVcfrd8augc+U2kHqHYgOWuIqi1D8jM1nS/Prjc=" /></div>
        
          <p><label for="user_email">Email</label><br />
          <input id="user_email" name="user[email]" size="30" type="email" value="" /></p>
      
          <p><label for="user_password">Password</label><br />
          <input id="user_password" name="user[password]" size="30" type="password" /></p>
      
          <p><label for="user_password_confirmation">Password confirmation</label><br />
          <input id="user_password_confirmation" name="user[password_confirmation]" size="30" type="password" /></p>

      
          <p><input id="user_submit" name="commit" type="submit" value="Sign up" /></p>
        </form>
          <a href="/users/sign_in">Sign in</a><br />
      
      
          <a href="/users/password/new">Forgot your password?</a><br />
      
      
          <a href="/users/unlock/new">Didn't receive unlock instructions?</a><br />
      </div>
.
.
.

user.rb

class User < ActiveRecord::Base
  # Include default devise modules. Others available are:
  # :token_authenticatable, :encryptable, :confirmable, :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable,
         :lockable, :timeoutable

  # Setup accessible (or protected) attributes for your model
  has_many :roles, :through => :assignments
  has_one :organization, :foreign_key => 'owner_id', :dependent => :destroy
  has_many :peons, :class_name => 'User', :through => :organization, :foreign_key => 'organization_id'
  belongs_to :company, :class_name => 'Organization', :foreign_key => 'organization_id', :dependent => :destroy
  accepts_nested_attributes_for :organization
  attr_accessible :email, :email_confirmation, :password, :password_confirmation,
                  :first_name, :last_name, :job_title, :organization_attributes, :organization_id,:remember_me
.
.
.