async function updatePositionHandler(req, res) {
  try {
    const data = [];
    req.on('data', (chunk) => {
      data.push(chunk);
    });
    req.on('end', async () => {
      const positionUpdate = JSON.parse(data).positionUpdate;
      await database.updatePosition(positionUpdate);
      res.statusCode = 200;
      res.end();
    });
  } catch {
    res.statusCode = 401;
    res.end();
  }
}
Handler for a users PUT request. Update a user's position in the users table.
@param {!Object} req The HTTP request object.
@param {!Object} res The HTTP response object.
@private