Fixed #17625 -- Mention in the management command docs that modules with an…

Fixed #17625 -- Mention in the management command docs that modules with an underscore prefix are ignored and not dissplayed in the list of commands.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17440 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/howto/custom-management-commands.txt

@@ -9,8 +9,9 @@ command for the ``polls`` application from the
 :doc:`tutorial</intro/tutorial01>`.
 
 To do this, just add a ``management/commands`` directory to the application.
-Each Python module in that directory will be auto-discovered and registered as
-a command that can be executed as an action when you run ``manage.py``::
+Each Python module in that directory will be auto-discovered. Modules having
+names not starting with an underscore will be registered as commands that can be
+executed as an action when you run ``manage.py``::
 
     polls/
         __init__.py
@@ -19,6 +20,7 @@ a command that can be executed as an action when you run ``manage.py``::
             __init__.py
             commands/
                 __init__.py
+                _private.py
                 closepoll.py
         tests.py
         views.py
@@ -26,6 +28,8 @@ a command that can be executed as an action when you run ``manage.py``::
 In this example, the ``closepoll`` command will be made available to any project
 that includes the ``polls`` application in :setting:`INSTALLED_APPS`.
 
+The ``_private.py`` module will not be available as a management command.
+
 The ``closepoll.py`` module has only one requirement -- it must define a class
 ``Command`` that extends :class:`BaseCommand` or one of its
 :ref:`subclasses<ref-basecommand-subclasses>`.