title: How to add additional params to a button_to form?
body: <p>I want to have a <code>Submit</code> button. It updates one field on the submission; <code>submission.state = :submitted</code></p>
  
  <p>Now, I could make a custom route and a custom action and just post to that. But that seems really heavy-handed. Especially since I'll also have a <code>reject</code> button and possibly more. Needing a custom route &amp; action for each of those seems downright silly to me.</p>
  
  <p>It would be much nicer if I could do something like</p>
  
  <pre><code>button_to "Submit", submission_url(submission), :method =&gt; :put, :submission =&gt; { :state =&gt; :submitted }
  </code></pre>
  
  <p>Which would post to the submission's <code>update</code> method and update only the desired field.</p>
  
  <p>But that doesn't work. How can I make it work? Or do you have a better idea of how to do this?</p>