Fixed #19463 -- Added UUIDField

Uses native support in postgres, and char(32) on other backends.

docs/ref/databases.txt

@@ -92,7 +92,8 @@ below for information on how to set up your database correctly.
 PostgreSQL notes
 ================
 
-Django supports PostgreSQL 9.0 and higher.
+Django supports PostgreSQL 9.0 and higher. It requires the use of Psycopg2
+2.0.9 or higher.
 
 PostgreSQL connection settings
 -------------------------------

docs/ref/forms/fields.txt

@@ -888,6 +888,20 @@ For each field, we describe the default widget used if you don't specify
 
     These are the same as ``CharField.max_length`` and ``CharField.min_length``.
 
+``UUIDField``
+-------------
+
+.. versionadded:: 1.8
+
+.. class:: UUIDField(**kwargs)
+
+    * Default widget: :class:`TextInput`
+    * Empty value: ``''`` (an empty string)
+    * Normalizes to: A :class:`~python:uuid.UUID` object.
+    * Error message keys: ``required``, ``invalid``
+
+    This field will accept any string format accepted as the ``hex`` argument
+    to the :class:`~python:uuid.UUID` constructor.
 
 Slightly complex built-in ``Field`` classes
 -------------------------------------------

docs/ref/models/fields.txt

@@ -1012,6 +1012,31 @@ Like all :class:`CharField` subclasses, :class:`URLField` takes the optional
 :attr:`~CharField.max_length` argument. If you don't specify
 :attr:`~CharField.max_length`, a default of 200 is used.
 
+UUIDField
+---------
+
+.. versionadded:: 1.8
+
+.. class:: UUIDField([**options])
+
+A field for storing universally unique identifiers. Uses Python's
+:class:`~python:uuid.UUID` class. When used on PostgreSQL, this stores in a
+``uuid`` datatype, otherwise in a ``char(32)``.
+
+Universally unique identifiers are a good alternative to :class:`AutoField` for
+:attr:`~Field.primary_key`. The database will not generate the UUID for you, so
+it is recommended to use :attr:`~Field.default`::
+
+    import uuid
+    from django.db import models
+
+    class MyUUIDModel(models.Model):
+        id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+        # other fields
+
+Note that a callable (with the parentheses omitted) is passed to ``default``,
+not an instance of ``UUID``.
+
 Relationship fields
 ===================