Fixed #22748 -- Corrected post_migrate usage example.

    The database alias used for synchronization. Defaults to the ``default``

    database.

For example, ``yourapp/management/__init__.py`` could be written like::

For example, you could register a callback in an

:class:`~django.apps.AppConfig` like this::

    from django.apps import AppConfig

    from django.db.models.signals import post_migrate

    import yourapp.models

    def my_callback(sender, **kwargs):

        # Your specific logic here

        pass

    post_migrate.connect(my_callback, sender=yourapp.models)

    class MyAppConfig(AppConfig):

        ...

        def ready(self):

            post_migrate.connect(my_callback, sender=self)

post_syncdb

-----------