utd-control-panel/signup/.htaccess

RewriteEngine On

RewriteRule ^(/?signup)?/?([a-z]+)$ /signup/$2.php [L]
RewriteRule ^(/?signup)?/?([0-9])$ /signup/index.php [L]
RewriteRule ^(/?signup)?/?:([0-9]+)$ /signup/index.php?ref=$2 [L]