Document authentication

docs/install.rst

@@ -430,6 +430,18 @@ Additionally you will have to adjust :file:`weblate/settings.py`::
 
 .. note:: This is supported since Weblate 1.3.
 
+
+Authentication
+--------------
+
+By default Weblate uses Django built-in user database. Thanks to this, you can
+also import user database from other Django based projects (see
+:ref:`pootle-migration`). 
+
+But Django can be configured to authenticate against other means as well.
+Currently you have to register and confirm your email even when using other
+authentication backend.
+
 .. _appliance:
 
 Prebuilt appliance
@@ -584,6 +596,8 @@ recommended to put your site offline, while the migration is going on.
     all of them in Weblate's directory, for example by 
     ``find . -name '*.pyc' - delete``.
 
+.. _migration-pootle:
+
 Migrating from Pootle
 ---------------------