Note we don't cast negative votes when users remove their support. That
way we provide compatibility for institutions who have implemented real
negative votes (in case there are / will be any), and we also keep the
database meaningful: it's not that users downvoted something; they
simply removed their upvote.
Co-Authored-By: Javi Martín <javim@elretirao.net>
Co-Authored-By: Julian Nicolas Herrero <microweb10@gmail.com>