prevent re-registrations using a deleted username - not an issue with Friendica but could create a serious privacy issue with federated platforms

database.sql

@@ -861,3 +861,9 @@ INDEX ( `term` )
 ) ENGINE = MyISAM DEFAULT CHARSET=utf8;
 
 
+CREATE TABLE IF NOT EXISTS `userd` (
+`id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY ,
+`username` CHAR( 255 ) NOT NULL,
+INDEX ( `username` )
+) ENGINE = MyISAM DEFAULT CHARSET=utf8;
+