title: How do you sort Using Thinking Sphinx on Rails 3?
body: <p>I'm trying to accomplish a simple sort using parameters passed to my controller. I'm following the <a href="http://freelancing-god.github.com/ts/en/searching.html#sorting" rel="noreferrer">documentation</a> on the Searching &amp; Thinking Sphinx website and I'm met with the following error. What am I doing wrong?</p>
  
  <p>The following @places object is an instance of the think Sphinx class. </p>
  
  <pre><code> @places = Place.search(params[:q], :order =&gt; :created_at)
  
  ThinkingSphinx::SphinxError (index place_core: sort-by attribute 'created_at' not found):
  </code></pre>