Test for http://stackoverflow.com/questions/20373208/can-not-update-document-in-mongoose

app.js

mongoose = require('mongoose');
var _ = require('underscore');
var db = mongoose.createConnection('localhost', 'stack-test');
 
/* Schema definition */
var SellerSchema = new mongoose.Schema({
    created: {
        type: Date,
        default: Date.now
    },
    description: {
        type: String,
        default: '',
        trim: true
    },
    payment: {
        type: String,
        default: '',
        trim: true
    },
    address: {
        type: String,
        default: '',
        trim: true
    },
    shipping: {
        type: String,
        default: '',
        trim: true
    },
    price: {
       type: Number,
       default: 3000,
       min: 0
    },
});
 
/* Model declaration */
var Seller = db.model('Seller', SellerSchema)
 
var newSeller = new Seller({ description: "stack-test", address: "aaaaa" })
newSeller.save(function(err, user) {
  console.log(err)

 	console.log(user);
 	var id = user._id;
	var req_body = {
	            description: "xxxxx",
	            payment: "xxxxxxxxx",
	            shipping: "xxxxxxx",
	            price: "17",
	            address: "xxxxxx"
	    };

	Seller.findById(id, function (err,seller) { 
	        seller = _.extend(seller, req_body)
	        seller.save(function(err) {
	            console.log(err);
	            console.log(seller);
	        })
	    });
});

package.json

{
  "name": "test",
  "version": "0.0.1",
  "dependencies": {
    "mongoose": "3.1.2",
    "underscore": "~1.5.2"
  }
}