...

Staging & Production have a redirect in (/etc/apache2/sites-enabled/sufia-project.conf and sufia-project_ssl.conf for ssl enabled locations) to redirect sign up for account to the main page
        Redirect /users/sign_up http://staging.hydra.chemheritage.org
 To restart this without a full apache reset, comment the line in or out and use
sudo apachectl graceful

Disabled

...