Second click in RSVP confirmation shows an error

[jualvarez]

If a participant clicks twice on the RSVP confirmation link, the second time it throws an error. Also related, once the RSVP is confirmed it cannot be changed to cancelled, it throws the same error.

The error says: "Something went wrong with your RSVP link. Please contact us at with your name."

Participants get really anxious although the confirmation was received :)

[das-g]

We (Django Girls Zürich) just got contacted by an applicant saying she got the message

Something went wrong with your RSVP link. Please contact us at [email protected] with your name.

when clicking the RSVP link. (She didn't say anything about clicking it twice, but it's of course possible that that's what she did. Is there any way we as organizers can find out? It looks like her RSVP status was updated alright.)

UX-wise probably related to #121.