// Delete a candidate
app.delete('/api/candidate/:id', (req, res) => {
  const sql = `DELETE FROM candidates WHERE id = ?`;
  const params = [req.params.id];

  db.query(sql, params, (err, result) => {
    if (err) {
      res.statusMessage(400).json({ error: res.message });
    } else if (!result.affectedRows) {
      res.json({
        message: 'Candidate not found'
      });
    } else {
      res.json({
        message: 'deleted',
        changes: result.affectedRows,
        id: req.params.id
      });
    }
  });
});