var mongoose = require('mongoose');

mongoose.connect("mongodb://localhost/asso_ref");


var postSchema = new mongoose.Schema({
 title:String,
 content:String
});

var Post = mongoose.model("Post",postSchema);

var userSchema = new mongoose.Schema ({
  email:String,
  name:String,
  posts:[{
   type:mongoose.Schema.Types.ObjectId,
   ref:"Post" //match with .model>> ("POST") <<
  }]
});

var User = mongoose.model("user",userSchema);


User.create({
 email:"[email protected]",
 name:"Sirawit Mahanin"
});

Post.create({title:"Post 1", content:"This is post 1"}, 
 function(err,post) {
  if(!err){
   User.findOne({email:"[email protected]"},function(err,foundUser) {
    if(!err) {
     foundUser.posts.push(post);
     foundUser.save(function(err,post) {
      if(!err){
       console.log(post);
      }
     });  
    } 
   });
  }   
 }   
);

// FIND USER
User.find({email:"[email protected]"}).populate("posts").exec&#40;function(err,user&#41;{
 if(err){
  console.log(err);
 } else {
  console.log(user); 
 }
});