Added datetime column for disk_speed

Will be used for YABs history feature

my_idlers.sql

@@ -26,6 +26,7 @@ CREATE TABLE IF NOT EXISTS `disk_speed`
     `1m`           float    DEFAULT NULL,
     `1m_type`      char(4)  DEFAULT NULL,
     `1m_as_mbps`   float    DEFAULT NULL,
+    `datetime`     datetime DEFAULT CURRENT_TIMESTAMP,
     PRIMARY KEY (`server_id`)
 ) ENGINE = InnoDB
   DEFAULT CHARSET = latin1;

update.sql

@@ -0,0 +1,2 @@
+ALTER TABLE `disk_speed`
+    ADD COLUMN `datetime` DATETIME NULL DEFAULT CURRENT_TIMESTAMP AFTER `1m_as_mbps`;