title: How do I set an attribute of an object based on its relation to other objects' attributes?
body: <p>I have a simple golf app, and for each player I have <code>:total_score</code> and <code>:current_place</code> attributes.  I want Rails to define the <code>:current_place</code> attribute of each player based on whether that player's <code>:total_score</code> is higher or lower than the other players.</p>
  
  <p>In other words, if there are two players, and one has a <code>:total_score =&gt; 5</code>and the other has <code>:total_score =&gt; 4</code> I'd like Rails to make the first player's <code>:current_place =&gt; 1</code>, and the other player's <code>:current_place =&gt; 2</code>, and so on.  I basically want it to define the <code>:current_place</code> values based on the descending of the <code>:total_score</code> column. </p>