title: Search DateFields by Format A in Django Admin though they are stored in Format B
body: <p>Am building a Django app. And on the admin is is required to be able to search for items based on queries that might also include names of the month, year, etc.</p>
  
  <p>The problem (I can't seem to find a solution to this on SO or elsewhere), is that the default format for dates in Django (ok, the way the dates have been persisted to the datastore) is %Y-%m-%d, but I wish to be able to search on say query like "June" from the Django Admin search.</p>
  
  <p>How do I make it possible to search date fields using custom date formats, without converting the formats in which the dates are persisted?</p>