diff --git a/User.php b/User.php
index cfdecbb..d36cbb1 100644
--- a/User.php
+++ b/User.php
@@ -3,15 +3,14 @@
 class User
 {
     protected $is_connected = false;
-    protected $id, $display_name, $auth_method;
+    protected $external_id; //the user's ID on the external auth system (Object SID on LDAP)
+    protected $id; //the internal id to store locally user's datas
+    protected $display_name;
+    protected $auth_method;
     protected $groups =array();
 
     protected $db;
 
-    public function __sleep(){
-        return array('is_connected','id','display_name','auth_method','groups');
-    }
-
     public function get_id()
     {
         if($this->is_connected){
@@ -23,6 +22,7 @@ class User
     {
         return $this->is_connected;
     }
+
     public function get_auth_method()
     {
         if($this->is_connected){
@@ -34,10 +34,7 @@ class User
     {
         return $this->groups;
     }
-    public function set_db_obj($db){
-        $this->db = $db;
-        return $this;
-    }
+    
     public function __construct($db){
         $this->db = $db;
     }
diff --git a/User_CAS.php b/User_CAS.php
new file mode 100644
index 0000000..3474188
--- /dev/null
+++ b/User_CAS.php
@@ -0,0 +1,6 @@
+<?php
+
+class User_CAS extends User {
+
+    
+}
\ No newline at end of file
diff --git a/User_Manager.php b/User_Manager.php
index e6861b5..014c498 100644
--- a/User_Manager.php
+++ b/User_Manager.php
@@ -2,7 +2,46 @@
 
 class User_Manager
 {
+
+    private static $table_users = 'users';
+    private static $table_groups = 'groups';
+
+
+    const CREATE_TABLE_USERS_QUERY = "
+        CREATE TABLE %table_users% (
+            `id` int(11) NOT NULL AUTO_INCREMENT,
+            `login` varchar(16) NOT NULL,
+            `display_name` text NOT NULL,
+            `auth_method` enum('local','ldap','cas','none') NOT NULL,
+            `password` char(128) NOT NULL,
+            `external_uid` char(45) NOT NULL,
+            `admin` tinyint(1) NOT NULL,
+            `active` tinyint(1) NOT NULL DEFAULT '1',
+            `created_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
+            `created_by` int(11) NOT NULL,
+            `updated_time` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00' ON UPDATE CURRENT_TIMESTAMP,
+            `updated_by` int(11) NOT NULL,
+            PRIMARY KEY (`id`)
+        );
+        INSERT INTO TABLE %table_users% (id,login,display_name,auth_method,active,created_time,created_by)
+        VALUES (0,'','SYSTEM','none',0, NOW(),0);
+        ";
+
+    const CREATE_TABLE_GROUPS = "
+        CREATE TABLE %table_groups% ( 
+            `id` int(11) NOT NULL AUTO_INCREMENT,
+            `name` text NOT NULL,
+            `active` tinyint(1) NOT NULL DEFAULT '1',
+            `created_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
+            `created_by` int(11) NOT NULL,
+            `updated_time` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00' ON UPDATE CURRENT_TIMESTAMP,
+            `updated_by` int(11) NOT NULL,
+            PRIMARY KEY (`id`)
+        );
+    ";
+
     
+
     public function authentificate($db,$login, $password){
         $user = new User_Sql($db);
         if($user->authentificate($login,$password)){