Passed the whole user object to make use of the instance methods

```javascript
 User.setter.password = function (pass) {
        this.salt = this.makeSalt();
        this._password = this.encryptPassword(pass);
    };
    
  

    User.prototype.authenticate = function(plainText) {
        return this.encryptPassword(plainText) === this.password;
    }

    User.prototype.makeSalt =function(date) {
        return Math.round(((date || new Date()).valueOf() * Math.random())) + '';
    }

    User.prototype.encryptPassword = function(password) {
        return crypto.createHmac('sha1', this.salt).update(password).digest('hex');
    }
    User.beforeUpdate = function(next) {
        this.modified_on = new Date();
        next();
    }
    
   User.verifyPassword = function(userpassword,user) {

                return user.authenticate(userpassword);
        };
    
```