Fixed documentation typo in issue 131. Thanks, pootow

git-svn-id: https://django-tagging.googlecode.com/svn/trunk@154 83e7428b-ec2a-0410-86f2-bf466d0e5e72

Author: insin

docs/overview.txt

@@ -401,7 +401,7 @@ function::
    [<Tag: house>, <Tag: thing>]
 
 Tags are created, associated and unassociated accordingly when you use
-``update_tags`` and ``add_tags``::
+``update_tags`` and ``add_tag``::
 
    >>> Tag.objects.update_tags(widget, 'house monkey')
    >>> Tag.objects.get_for_object(widget)