Fixed #11398 - Added a pre_syncdb signal

docs/ref/signals.txt

@@ -360,6 +360,53 @@ Management signals
 
 Signals sent by :doc:`django-admin </ref/django-admin>`.
 
+pre_syncdb
+----------
+
+.. data:: django.db.models.signals.pre_syncdb
+   :module:
+
+Sent by the :djadmin:`syncdb` command before it starts to install an
+application.
+
+Any handlers that listen to this signal need to be written in a particular
+place: a ``management`` module in one of your :setting:`INSTALLED_APPS`. If
+handlers are registered anywhere else they may not be loaded by
+:djadmin:`syncdb`.
+
+Arguments sent with this signal:
+
+``sender``
+    The ``models`` module that was just installed. That is, if
+    :djadmin:`syncdb` just installed an app called ``"foo.bar.myapp"``,
+    ``sender`` will be the ``foo.bar.myapp.models`` module.
+
+``app``
+    Same as ``sender``.
+
+``create_models``
+    A list of the model classes from any app which :djadmin:`syncdb` plans to
+    create.
+
+
+``verbosity``
+    Indicates how much information manage.py is printing on screen. See
+    the :djadminopt:`--verbosity` flag for details.
+
+    Functions which listen for :data:`pre_syncdb` should adjust what they
+    output to the screen based on the value of this argument.
+
+``interactive``
+    If ``interactive`` is ``True``, it's safe to prompt the user to input
+    things on the command line. If ``interactive`` is ``False``, functions
+    which listen for this signal should not try to prompt for anything.
+
+    For example, the :mod:`django.contrib.auth` app only prompts to create a
+    superuser when ``interactive`` is ``True``.
+
+``db``
+    The alias of database on which a command will operate.
+
 post_syncdb
 -----------