@Override
public void onClick(AjaxRequestTarget target) {
Change change = new Change(user.username);
if (ticket.isVoter(user.username)) {
change.unvote(user.username);
} else {
change.vote(user.username);
}
app().tickets().updateTicket(repository, ticket.number, change);
setResponsePage(TicketsPage.class, getPageParameters());