title: ActiveRecord searching by pseudo attributes
body: <p>On my model I have the method</p>
  
  <pre><code>def complete?
      self.address_id &amp;&amp; self.user_id &amp;&amp; self.location
  end
  </code></pre>
  
  <p>Is it possible to do a search with activerecord for records where this is true or will I have to just check all of these columns are not nil in each lookup?</p>