Added create sequence (and used) in postgre install for drafts

Signed-off-by: emanuele <emanuele45@gmail.com>

other/install_2-1_postgresql.sql

@@ -2565,12 +2565,18 @@ VALUES (1, 1, 1, 1, 0, 0);
 # --------------------------------------------------------
 
 
+#
+# Sequence for table `user_drafts`
+#
+
+CREATE SEQUENCE {$db_prefix}user_drafts_seq;
+
 #
 # Table structure for table `user_drafts`
 #
 
 CREATE TABLE {$db_prefix}user_drafts (
-  id_draft int unsigned NOT NULL auto_increment,
+  id_draft int default nextval('{$db_prefix}user_drafts_seq'),
   id_topic int unsigned NOT NULL default '0',
   id_board smallint unsigned NOT NULL default '0',
   id_reply int unsigned NOT NULL default '0',