title: Rails 3.2 - Why is simple_form is not generating any markup for my nested attributes?
body: <p>I've spent about 5 straight hours at this and keep ending up back at square one...time to ask for time help!</p>
  
  <p>I am using Rails 3.2, devise and simple_form, I am trying to build a form that will allow a user to register (email, password) &amp; allow them to create a simple listing object - all on the one page. However none of my nested attributes for the user are appearing on the markup when the /listings/new page loads &amp; I cannot figure out why.</p>
  
  <p>Here is what I have:</p>
  
  <p>Listing controller:</p>
  
  <pre><code>def new
    @listing = Listing.new
  
    respond_to do |format|
      format.html # new.html.erb
      format.json { render json: @listing }
    end
  end
  </code></pre>
  
  <p>Listing model:</p>
  
  <pre><code>class Listing &lt; ActiveRecord::Base
    has_one :address
    belongs_to :category
    belongs_to :user
  
    accepts_nested_attributes_for :address
    accepts_nested_attributes_for :user
  end
  </code></pre>
  
  <p>User model:</p>
  
  <pre><code>class User &lt; ActiveRecord::Base
    has_many :listings
    devise :database_authenticatable, :registerable, :validatable
    attr_accessible :email, :password, :password_confirmation, :remember_me
  
  end
  </code></pre>
  
  <p>New Listings Form:</p>
  
  <pre><code>&lt;%= simple_form_for(@listing) do |f| %&gt;
  
  &lt;%= f.label :listing_type %&gt;
  &lt;%= f.collection_select :listing_type, [["Creative","Creative"]], :first, :last%&gt;
  
    &lt;%= f.simple_fields_for :user do |u| %&gt;
      &lt;%= u.label :email %&gt;
      &lt;%= u.input_field :email %&gt;
  
      &lt;%= u.label_for :password %&gt;
      &lt;%= u.input_field :password %&gt;
  
      &lt;%= u.label_for :password_confirmation %&gt;
      &lt;%= u.input_field :password_confirmation %&gt;
    &lt;% end %&gt;
  
  &lt;% end %&gt;
  </code></pre>
  
  <p>My head is melted looking at this, any help is much appreciated! </p>