title: "accepts_nested_attributes_for" does not render fields in _form.haml partial
body: <p>I've got a problem that is giving me a headache.</p>
  
  <p>in my Terminal I see that the Trail table is looked up. There is some dummy stuff in that table.</p>
  
  <pre><code>DEBUG - Account Load (0.4ms)  SELECT "accounts".* FROM "accounts" WHERE "accounts"."id" = 1 LIMIT 1
  DEBUG - Trail Load (0.2ms)  SELECT "trails".* FROM "trails"
  DEBUG - TEMPLATE (0.0004ms) /adventures/new
  DEBUG - TEMPLATE (0.0002ms) /layouts/application
  DEBUG - TEMPLATE (0.0004ms) /adventures/_form
  DEBUG - TEMPLATE (0.0003ms) /base/_sidebar
  DEBUG -      GET (0.0644ms) /admin/adventures/new - 200 OK
  </code></pre>
  
  <p>I've tried and erred on this for way to long, now this is using the same set up as Padrino's guide suggests in their "accepts_nested_attributes_for" guide. Still I can't get the form to show up in my browser for editing.</p>
  
  <p>.../views/adventures/_form.haml</p>
  
  <pre><code>.group_trail
    -f.fields_for :trails do |trail_form|
      =trail_form.label :start
      =trail_form.text_field :start
  =trail_form.label :end
      =trail_form.text_field :end
      =trail_form.label :via
      =trail_form.text_field :via
      -unless trail_form.object.new_record?
        =trail_form.check_box '_destroy'
        =trail_form.label '_destroy', :caption =&gt; "Remove"
  </code></pre>
  
  <p>In the html source there is rendered the group_trail but none of the forms with in.          </p>
  
  <pre><code>...     
  &lt;/div&gt;
   &lt;div class='group_trail'&gt;
    &lt;/div&gt;
      &lt;div class='group navform wat-cf'&gt;
      &lt;input class="button" value="Save" type="submit" /&gt;
  </code></pre>
  
  <p>in my models I have:</p>
  
  <pre><code>class Adventure &lt; ActiveRecord::Base  
      has_many :trails, :class_name =&gt; 'Adventure'
      accepts_nested_attributes_for :trails, :allow_destroy =&gt; true
  end
  
  class Trail &lt; ActiveRecord::Base 
       belongs_to :adventure
  end
  </code></pre>
  
  <p>I did have a adventure_id in my trails table, but I've reverted to simpler method of trying for now, since it's said not to be needed for this association of nested_attributes. </p>
  
  <p>If I run it with the adventure_id in trails table there is like it tries to select the adventure_id from the adventure table.</p>
  
  <pre><code>     DEBUG - Account Load (0.3ms)  SELECT "accounts".* FROM "accounts" WHERE "accounts"."id" = 1 LIMIT 1
        DEBUG - Trail Load (0.2ms)  SELECT "trails".* FROM "trails"
        DEBUG - Adventure Load (0.2ms)  SELECT "adventures".* FROM "adventures" WHERE "adventures"."id" = ? LIMIT 1  [["id", "9"]]
        DEBUG - TEMPLATE (0.0004ms) /adventures/edit
        DEBUG - TEMPLATE (0.0002ms) /layouts/application
        DEBUG - TEMPLATE (0.0003ms) /adventures/_form
        DEBUG - Adventure Load (0.3ms)  SELECT "adventures".* FROM "adventures" WHERE "adventures"."adventure_id" = 9
        DEBUG - SQLite3::SQLException: no such column: adventures.adventure_id: SELECT "adventures".* FROM "adventures"  WHERE "adventures"."adventure_id" = 9
      ActiveRecord::StatementInvalid - SQLite3::SQLException: no such column: adventures.adventure_id: SELECT "adventures".* FROM "adventures"  WHERE "adventures"."adventure_id" = 9: 
  </code></pre>
  
  <p>Does anyone know why it searches the adventures table instead of trials table for the adventure_id?</p>
  
  <p>Can anyone point at what I'm doing wrong? or point me in the right direction to figure this out?</p>