Added a new "auth" field to the user table. This field contains the

authentication mechanism used to create that user record.

Also added code to upgrade existing systems to have entries in that
field, and for new users to also have that field defined.

This will allow us to later improve the login procedure to be able to
handle various types of authentication.

lib/moodlelib.php

@@ -716,6 +716,7 @@ function create_user_record($username, $password) {
         }
     }
 
+    $newuser->auth = $CFG->auth;
     $newuser->username = $username;
     $newuser->password = md5($password);
     $newuser->lang = $CFG->lang;