title: on Rails, is f.submit in a form_for newer than submit_tag?
body: <p>some books or even the rails api uses</p>
  
  <pre><code>form_for ...
    ...
    submit_tag ...
  end
  </code></pre>
  
  <p>and i found that the Rails 2.3.2 Scaffold uses</p>
  
  <pre><code>f.submit "Create"
  </code></pre>
  
  <p>instead...  and this is not in the rails api doc.  Is this a new
  addition and is it suppose to replace submit_tag?</p>