update index table _tags_id

Author: vuthao

modules/download/action_mysql.php

@@ -135,6 +135,8 @@
   id int(11) NOT NULL,
   did mediumint(9) NOT NULL,
   keyword varchar(65) NOT NULL
+  UNIQUE KEY id_tid (id,did),
+  KEY did (did)
 )ENGINE=MyISAM";
 
 $maxfilesize = min($global_config['nv_max_size'], nv_converttoBytes(ini_get('upload_max_filesize')), nv_converttoBytes(ini_get('post_max_size')));