added documentation on Model attributes

docs/topics/db/models.txt

@@ -663,6 +663,19 @@ Meta`` to a model is completely optional.
 A complete list of all possible ``Meta`` options can be found in the :doc:`model
 option reference </ref/models/options>`.
 
+.. _model-attributes:
+
+Model attributes
+================
+
+:attr:`~objects`
+    The most important attribute of a model is the 
+    :class:`~django.db.models.Manager`, which is the interface through which 
+    database query operations are provided to Django models and is used to 
+    :ref:`retrieve the instances <retrieving-objects>` from the database. If no 
+    custom Manager is defined, the default name is ``objects``. Managers are 
+    only accessible via model classes, not the model instances. 
+
 .. _model-methods:
 
 Model methods

docs/topics/db/queries.txt

@@ -129,6 +129,8 @@ go, include multiple arguments in the call to
 
 Django will complain if you try to assign or add an object of the wrong type.
 
+.. _retrieving-objects:
+
 Retrieving objects
 ==================