feat(es_extended): add SSN

[SQL]/legacy.sql

@@ -385,6 +385,7 @@ CREATE TABLE `society_moneywash` (
 
 CREATE TABLE `users` (
   `identifier` varchar(60) NOT NULL,
+	`ssn` VARCHAR(11) NOT NULL,
   `accounts` longtext DEFAULT NULL,
   `group` varchar(50) DEFAULT 'user',
   `inventory` longtext DEFAULT NULL,
@@ -847,6 +848,9 @@ ALTER TABLE `users`
   ADD PRIMARY KEY (`identifier`),
   ADD UNIQUE KEY `id` (`id`);
 
+ALTER TABLE `users`
+  ADD UNIQUE KEY `unique_ssn` (`ssn`);
+
 --
 -- Indexes for table `user_licenses`
 --