Add docs for Moderation publish and unpublish signal (#163)

docs/signals.rst

@@ -50,3 +50,101 @@ Arguments sent with this signal:
 ``rework``
     A :class:`bool` value specifying if this was the first time the
     collection was submitted, or a rework of its moderation requests
+
+
+
+``published``
+------------------------
+
+.. attribute:: djangocms_moderation.published
+   :module:
+
+.. ^^^^^^^ this :module: hack keeps Sphinx from prepending the module.
+
+Sent when a :ref:`moderation_collection` is being published
+
+Arguments sent with this signal:
+
+``sender``
+    :class:`djangocms_moderation.models.ModerationCollection` class
+
+``collection``
+    A :class:`djangocms_moderation.models.ModerationCollection` instance
+    which was submitted to be published.
+
+``moderator``
+    A :class:`django.contrib.auth.models.User` associated with the collection which is the moderator of the collection.
+
+``moderation_requests``
+    A list of :class:`djangocms_moderation.models.ModerationRequest` instances
+    which were published.
+
+    .. note::
+
+        It's possible for this list to contain only some of the requests
+        belonging to the collection being moderated,
+        because only some of the requests were published.
+
+``workflow``
+    An instance of :class:`djangocms_moderation.models.Workflow` which was used for this collection.
+
+
+``unpublished``
+------------------------
+
+.. attribute:: djangocms_moderation.unpublished
+   :module:
+
+.. ^^^^^^^ this :module: hack keeps Sphinx from prepending the module.
+
+Sent when a :ref:`moderation_collection` is being unpublished
+
+Arguments sent with this signal:
+
+``sender``
+    :class:`djangocms_moderation.models.ModerationCollection` class
+
+``collection``
+    A :class:`djangocms_moderation.models.ModerationCollection` instance
+    which was submitted to be unpublished.
+
+``moderator``
+    A :class:`django.contrib.auth.models.User` associated with the collection which is the moderator of the collection.
+
+``moderation_requests``
+    A list of :class:`djangocms_moderation.models.ModerationRequest` instances
+    which were unpublished.
+
+    .. note::
+
+        It's possible for this list to contain only some of the requests
+        belonging to the collection being moderated,
+        because only some of the requests were unpublished.
+
+``workflow``
+    An instance of :class:`djangocms_moderation.models.Workflow` which was used for this collection.
+
+
+
+How to use the moderation publish signal for a collection
+---------------------------------------------------------------------
+
+The CMS used to provide page publish and unpublish signals which have since been removed in DjangoCMS 4.0. You can instead use the signals provided above to replace these.
+
+Djangocms-moderation provides a way to take further actions once a collection has been published. The `published` event is the last event executed for a moderation.
+
+
+.. code-block:: python
+
+    from django.dispatch import receiver
+
+    from cms.models import PageContent
+
+    from djangocm_moderation.signals import published
+
+
+    @receiver(published)
+    def do_something_on_publish_event(*args, **kwargs):
+        # all keyword arguments can be found in kwargs
+        # pass
+