Redirect request for Chargify Direct Signups page

[woodchopgirl]

@drewblas

Previously I had requested that the Signup page be added / then dropped. We viewed the document, once it had been re-added and it appeared incomplete, which is not ideal via #152

However now, we realise that customers still possess the link:

https://docs.chargify.com/chargify-direct-signups

Should we request a redirect in this situation? Or re-add the document?

Redirect would be as follows:

Old URL:
https://docs.chargify.com/chargify-direct-signups

New URL:
https://docs.chargify.com/api-signups