public function adiciona(Participante $participante)
{
$query = 'insert into Participante(nome, sobrenome, email)
values(?, ?, ?)';
$stmt = $this->conexao->prepare($query);
$stmt->bind_param('sss', $participante->getNome(), $participante->getSobrenome(), $participante->getEmail());
$stmt->execute();
}