title: Form_For New Related Model
body: <p>So in my app I have a Person model which <code>has_many</code> Descriptions. I now need a form on each person's show page for to add a new description for that person. So far I have the following form. However it isn't passing the person's ID to the Description Create action.</p>
  
  <p><strong>Form</strong></p>
  
  <pre><code>&lt;%= form_for @person.descriptions.new do |f| %&gt;
  
      &lt;fieldset class="input"&gt;
          &lt;%= f.label :name %&gt;
          &lt;%= f.text_field :name %&gt;
      &lt;/fieldset&gt;
  
      &lt;fieldset class="input"&gt;
          &lt;%= f.label :description %&gt;
          &lt;%= f.text_area :description %&gt;
      &lt;/fieldset&gt;
  
      &lt;fieldset class="button"&gt;
          &lt;%= f.submit "Post" %&gt;
      &lt;/fieldset&gt;
  
  &lt;% end %&gt;
  </code></pre>
  
  <p><strong>Params Passed</strong></p>
  
  <pre><code>{"utf8"=&gt;"✓",
   "authenticity_token"=&gt;"OQY8Xcfm6wtWHXp9GjFfM4ICX79smPwyvfVcaDn+C2s=",
   "description"=&gt;{"name"=&gt;"Test",
   "description"=&gt;"This is a test"},
   "commit"=&gt;"Post"}
  </code></pre>