Ruby on Rails: Nested form not working

Currently, my nested form (the one for address) isn't showing up. It just shows the h1, and the submit button...

Relevant code:

class Address < ActiveRecord::Base
  belongs_to :user
  belongs_to :poll_option
  apply_addresslogic :fields => [[:number, :street], :city, [:state, :zip_code]]
end

class PollOption < ActiveRecord::Base
  belongs_to :poll
  has_one :address

  accepts_nested_attributes_for :address, :allow_destroy => true

end

<h1>Add a new address for voting</h1>

<% form_for @poll_option do |po_form| %>
  <%= po_form.error_messages %>

  <%= po_form.hidden_field :poll_id, :value => @poll.id %>

  <% po_form.fields_for :address do |addr_form| %>
      <%= addr_form.label :number %><br />
      <%= addr_form.text_field :number %><br />
      <br />
      <%= addr_form.label :street %><br />
      <%= addr_form.text_field :street %><br />
      <br />
      <%= addr_form.label :city %><br />
      <%= addr_form.text_field :city %><br />
      <br />
      <%= addr_form.label :state %><br />
      <%= addr_form.text_field :state %><br />
      <br />
      <%= addr_form开发者_Python百科.label :zip_code %><br />
      <%= addr_form.text_field :zip_code %><br />
      <br />
      <br />

  <% end %>

  <%= submit_tag "Create address and vote for this one" %>
<% end %>

If you're using Rails 3, you should be using <%= form_for .. and <%= f.fields_for ..., as the = on the tag indicates that it will output.

Additionally, in your controller's action that renders this form you need to be building the object (@poll_option.build_address or similar) so that the fields_for has an object to render.