Fixed #23575 -- Added a code example for custom AdminSite.

    this class is created as ``django.contrib.admin.site`` and you can

    register your models and ``ModelAdmin`` instances with it.

    If you'd like to set up your own administrative site with custom

    behavior, however, you're free to subclass ``AdminSite`` and override

    or add anything you like. Then, simply create an instance of your

    ``AdminSite`` subclass (the same way you'd instantiate any other

    Python class), and register your models and ``ModelAdmin`` subclasses

    with it instead of using the default.

    When constructing an instance of an ``AdminSite``, you can provide

    a unique instance name using the ``name`` argument to the constructor. This

    instance name is used to identify the instance, especially when

    :ref:`reversing admin URLs <admin-reverse-urls>`. If no instance name is

    provided, a default instance name of ``admin`` will be used.

    See :ref:`customizing-adminsite` for an example of customizing the

    :class:`AdminSite` class.

``AdminSite`` attributes

------------------------

        url(r'^admin/', include(admin.site.urls)),

    ]

In this example, we register the ``AdminSite`` instance

``myproject.admin.admin_site`` at the URL ``/myadmin/`` ::

.. _customizing-adminsite:

    # urls.py

    from django.conf.urls import include, url

    from myproject.admin import admin_site

Customizing the :class:`AdminSite` class

----------------------------------------

If you'd like to set up your own admin site with custom behavior, you're free

to subclass ``AdminSite`` and override or add anything you like. Then, simply

create an instance of your ``AdminSite`` subclass (the same way you'd

instantiate any other Python class) and register your models and

``ModelAdmin`` subclasses with it instead of with the default site. Finally,

update :file:`myproject/urls.py` to reference your :class:`AdminSite` subclass.

.. snippet::

    :filename: myapp/admin.py

    from django.contrib.admin import AdminSite

    from .models import MyModel

    class MyAdminSite(AdminSite):

        site_header = 'Monty Python administration'

    admin_site = MyAdminSite(name='myadmin')

    admin_site.register(MyModel)

.. snippet::

    :filename: myproject/urls.py

    from myapp.admin import admin_site

    urlpatterns = [

        url(r'^myadmin/', include(admin_site.urls)),