generateAuthTokens = async (user) => {
  const accessTokenExpires = moment().add(config.jwt.accessExpirationMinutes, 'minutes');
  const accessToken = generateToken(user.id, accessTokenExpires, tokenTypes.ACCESS);

  const refreshTokenExpires = moment().add(config.jwt.refreshExpirationDays, 'days');
  const refreshToken = generateToken(user.id, refreshTokenExpires, tokenTypes.REFRESH);
  await saveToken(refreshToken, user.id, refreshTokenExpires, tokenTypes.REFRESH);

  return {
    access: {
      token: accessToken,
      expires: accessTokenExpires.toDate(),
    },
    refresh: {
      token: refreshToken,
      expires: refreshTokenExpires.toDate(),
    },
  };
}
Generate auth tokens
@param {User} user
@returns {Promise<Object>}