User Timestamps by default

This small change will allow anyone using legacy to quickly see via sql when a user account was created and when the user was last active.

[SQL]/legacy.sql

@@ -400,6 +400,8 @@ CREATE TABLE `users` (
   `id` int(11) NOT NULL,
   `disabled` TINYINT(1) NULL DEFAULT '0',
   `last_property` varchar(255) DEFAULT NULL
+  `created_at` timestamp NULL DEFAULT CURRENT_TIMESTAMP,
+  `last_seen` timestamp NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP
 ) ENGINE=InnoDB;
 
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