title: Intercept find_by_attribute method active record
body: <p>I have a model that has a cellphone</p>
  
  <p>Cellphones are store using a particular format in the database.
  I'd like to intercept User.find_by_cellphone("1234567890") and normalize the cellphone, then call the "real" find_by_cellphone("123-456-7890").</p>
  
  <p>How would I go about that? I was thinking of renaming find_by_cellphone to ar_find_by_cellphone then overwrite find_by_cellphone and call ar_find_by_cellphone in it. Any other ideas?</p>