title: fields_for not rendering association name (belongs_to relationship)
body: <p>I'm trying to create the form to create an event.  Events belong_to a creator (of class user), and the form includes fields_for the creator.  </p>
  
  <p>Largely the form is working - it renders everything else properly, and the create action processes it properly when the fields_for @event.creator section is commented out.  The fields_for tag is rendering event[user] tags instead of event[creator], though, and i can't figure out why.  Ideas?  Here are the relevant excerpts.</p>
  
  <p>(in views/events/new.html.erb)</p>
  
  <pre><code>&lt;%= form_for @event do |form| %&gt;
     &lt;%= render :partial =&gt; '/events/form', :object =&gt; form %&gt;
     &lt;%= form.submit 'Go!' %&gt;
  &lt;% end %&gt;
  </code></pre>
  
  <p>(in events/_form.html.erb)</p>
  
  <pre><code>...
  
  &lt;% if !signed_in? %&gt;
    To create your event, please provide an email address and create a password. &lt;br /&gt;
  
  
    &lt;%= form.fields_for @event.creator do |uf| %&gt;
      &lt;div class="email_field"&gt;
        &lt;%= uf.label :email %&gt;
        &lt;%= uf.text_field :email, :type =&gt; "email" %&gt;
      &lt;/div&gt;
  
  ...
    &lt;% end %&gt;
  &lt;% end %&gt;
  </code></pre>
  
  <p>(controllers/events_controller.rb)</p>
  
  <pre><code>def new
     @event = Event.new
  
     if !signed_in?
       @event.build_creator
     end
  
     respond_to do |format|
       format.html # new.html.erb
       format.xml  { render :xml =&gt; @event }
     end
   end
  </code></pre>
  
  <p>(models/event.rb)</p>
  
  <pre><code>belongs_to :creator, :class_name =&gt; "User"
  accepts_nested_attributes_for :creator
  </code></pre>
  
  <p>Largely this works, but the form elements render as </p>
  
  <pre><code>&lt;div class="email_field"&gt; 
    &lt;label for="event_user_email"&gt;Email&lt;/label&gt; 
    &lt;input id="event_user_email" name="event[user][email]" size="30" type="email" /&gt; 
  &lt;/div&gt; 
  &lt;div class="password_field"&gt; 
    &lt;label for="event_user_password"&gt;Password&lt;/label&gt; 
    &lt;input id="event_user_password" name="event[user][password]" size="30" type="password" /&gt; 
  &lt;/div&gt;
  ...
  </code></pre>
  
  <p>the issue here is event_user and event[user] instead of event_creator and event[creator]; when i submit the form i get an error that event doesn't have a User field.</p>