Doc: add alter table person

Documentation/UseCase.rst

@@ -90,13 +90,16 @@ Table: Person
       `firstName` varchar(64) NOT NULL DEFAULT '',
       `email` varchar(128) NOT NULL,
       `account` varchar(128) NOT NULL,
-      `auth`  varchar(32) NOT NULL,
+      `auth`  varchar(32) NOT NULL DEFAULT '',
       `authExpire` datetime DEFAULT NULL
     ) ENGINE=InnoDB DEFAULT CHARSET=utf8 PACK_KEYS=1;
 
     ALTER TABLE `Person` ADD PRIMARY KEY (`id`);
     ALTER TABLE `Person` MODIFY `id` int(11) UNSIGNED NOT NULL AUTO_INCREMENT;
 
+or::
+
+    ALTER TABLE `person` ADD `auth` VARCHAR(32) NOT NULL DEFAULT '' AFTER `account`, ADD `auth_expired` DATETIME DEFAULT NULL AFTER `auth`;
 
 Registration
 ^^^^^^^^^^^^