Adrian

I think the placement of the button is nice, but it looks really bad when there are no documents yet in a registration:  I suggest keeping the box title...

  - The title should stay the same - There shouldn't be two titles in case of existing documents - The message I proposed should be in the "body"...

> It would be nice to make the shown social providers configurable (per site would be ok) If any API credentials etc were needed I'd agree, but since that's not...

Wouldn't it make sense to use a token instead of allowing access by just knowing the (easy to enumerate) URL, similar like we do for private surveys?

What I mean is that it'd just affect the link you send - it's still be the same link for everyone. So I think for your usecase it would work...

How about `form_token`? In principle UUIDs are unique enough to share the same query arg - so you could also first check if it's a valid registration token and otherwise...

"To register, use link" isn't correct English. My suggestion would be to show it nicely as a box in the registration management dashboard, similar to what we do for surveys....

@vtran99 I fixed a few issues and as far as I'm concerned it's good to be merged now. Feel free to have a last look as well.

@foxbunny I rebased this PR to the latest master and applied a few minor fixes for very straightforward things I encountered while testing. I think finishing this PR could actually...

FYI I've forcepushed a rebased version of this PR since I fixed an unrelated bug in the room booking form earlier today