- Fix invitation code.
- Fix invitation code.

Thanks to Akuket and xet7 !

Closes #1749

GhassenRjab/wekan,libreboard/libreboard,GhassenRjab/wekan,libreboard/libreboard,wekan/wekan,wekan/wekan,wekan/wekan,wekan/wekan,GhassenRjab/wekan,wekan/wekan