-- add server timezone
INSERT INTO `conf` VALUES ('site.tz','USA Eastern');

-- add timezone column for users
ALTER TABLE `users` ADD `timezone` VARCHAR(50) COLLATE utf8_unicode_ci NOT NULL AFTER `fullname`;

-- set default user timezone
UPDATE `users` SET `timezone` = 'USA Eastern' WHERE id = 1;

-- update timezones for current log entries
UPDATE `log` SET `created_at` = CONVERT_TZ(created_at, '-05:00', '+00:00') WHERE 1;