I suggest having the chat link routing to #general as opposed to the registration/invite page for the reason that it is significantly more convenient and will be accessed more, the link to the invitation could then be made available via a stickied thread, another option would be to have a icon such as #irc(even though slack is now being used) on the messages bar linking to #general and then having the chat registration available in its current position.(sorry for the long sentence)
Added a "already registered" link. Direct redirect is not possible as we don't know if the user has an account or not until they enter the e-mail.
