Fixed #7284 -- Provided an example for the use of the search_fields clause on...

    search_fields = ['foreign_key__related_fieldname']

For example, if you have a blog entry with an author, the following definition

would enable search blog entries by the email address of the author::

    search_fields = ['user__email']

When somebody does a search in the admin search box, Django splits the search

query into words and returns all objects that contain each of the words, case

insensitive, where each word must be in at least one of ``search_fields``. For