Updated link to Django Debug Toolbar homepage.

Thanks to rowynm AT gmail DOT com for the report and to Claude Paroz for
the patch.

Fixes #17543.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17376 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/topics/db/optimization.txt

@@ -29,7 +29,7 @@ readability of your code. **All** of the suggestions below come with the caveat
 that in your circumstances the general principle might not apply, or might even
 be reversed.
 
-.. _django-debug-toolbar: http://robhudson.github.com/django-debug-toolbar/
+.. _django-debug-toolbar: https://github.com/django-debug-toolbar/django-debug-toolbar/
 
 Use standard DB optimization techniques
 =======================================