invitation_accepted_at should be nil if the user signs up

[krue-doug]

I noticed that if there is a pending invite and if the user doesn't go through the link and signs up normally then the invite is marked as accepted. The invite should only be marked as accepted if and only they set the password through the invitation link. Any suggestions for making this so?

[scambra]

You may change line 10 in registrations controller, to clear invitation token. Some tests may need changes.

https://github.com/scambra/devise_invitable/blob/master/app/controllers/devise_invitable/registrations_controller.rb#L10