text: const { body } = require('express-validator');
  
  exports.signupValidator = [
    body('username').exists().isString().isLength({ min: 4 }).bail(),
    body('password').exists().isString().isLength({ min: 4 }).bail(),
    body('confirmPassword').exists().isString()
      .custom((value, { req }) => value === req.body.password)
  ];