title: NodeJS, Mongoose: How to get related data using mongoose
body: <p>I have 2 collections and they are in one-to-many relationship.
  How can i get related data as nested document using mongoose?</p>
  
  <p>I have 2 schemas and they are related like this..</p>
  
  <pre><code>var userSchema = mongoose.Schema({
    name : String,
    age : Number,
  });
  
  var postSchema = mongoose.Schema({
    title: String,
    body: String,
    user: {type: mongoose.Schema.Types.ObjectId, ref:'User'}
  });
  </code></pre>
  
  <p>and there are data in mongodb..</p>
  
  <pre><code>//user:
  {
    _id:"5694934cab2816601db06291", 
    name:"John", 
    age:16
  },
  {
    _id:"5694934cab2816601db06292", 
    name:"Kim", 
    age:61
  }
  
  //post : 
  {
    _id:"569494e5ab2816601db06293",
    title:"hi",
    body:"nice to meet you",
    user:"5694934cab2816601db06291"
  },
  {
    _id:"569494e5ab2816601db06294", 
    title:"hello",
    body:"how are you",
    user:"5694934cab2816601db06292"
  }
  </code></pre>
  
  <p>What is the best way to get results like this using mongoose?</p>
  
  <pre><code>{
    _id:"569494e5ab2816601db06293", 
    title:"hi", 
    body:"nice to meet you", 
    user:{
           _id:"569494e5ab2816601db06294",
           name:"John", 
           age:16
    }
  },
  {
    _id:"569494e5ab2816601db06294",
    title:"hello",
    body:"how are you",
    user:{
           _id:"569494e5ab2816601db06292",
           name:"Kim", 
           age:61
    }
  }
  </code></pre>