title: ActiveRecord Find By Year, Day or Month on a Date field
body: <p>I have an ActiveRecord model that has a date attribute.  Is it possible to utilize that date attribute to find by Year, Day and Month:</p>
  
  <pre><code>Model.find_by_year(2012)
  Model.find_by_month(12)
  Model.find_by_day(1)
  </code></pre>
  
  <p>or is it simply possible to find_by_date(2012-12-1).</p>
  
  <p>I was hoping I could avoid creating Year, Month and Day attributes. </p>