title: Is there a way to make ActiveRecord write 'WHERE (a,b) in ((1,2),(3,4))' using AR finders
body: <p>Is there a way to make ActiveRecord write 'WHERE (a,b) in ((1,2),(3,4))' using AR finders.</p>
  
  <p>I would think</p>
  
  <pre><code>Widget.find(:all, :conditions =&gt; ['(a,b) in (?)', [[1,2][3,4]]])
  </code></pre>
  
  <p>but the inner arrays get converted to YAML?!?! Right now I'm using find_by_sql. Is there a better way to write this?</p>