router.post('/register', (req, res) => {
  const {errors, isValid} = validateRegisterInput(req.body);
  if(!isValid) {
    return res.status(400).json(errors);
  }

  User.findOne({email: req.body.email})
  .then(user => {
    if(user) {
      errors.email = 'Email already exists';
      return res.status(400).json(errors);
    }

      const newUser = new User({
        name: req.body.name,
        email: req.body.email,
        avatar,
        password: req.body.password
      })

      bcrypt.genSalt(10, (err, salt) => {
        bcrypt.hash(newUser.password, salt, (err, hash) => {
          if(err) throw err;
          newUser.password = hash;
          newUser.save()
          .then(user => res.json(user))
          .catch(err => console.log(err))
        })
      })
    }
  })
})