title: How to populate reference field in virtual method in Mongoose?
body: <p>I have following schema.</p>
  
  <pre><code>var ItemSchema = new Schema({
  name : String
  ,location: {
      address: { type: String, default:''}, 
      geolocation: {longitude: Number, latitude:Number}, 
      place : {type: Schema.Types.ObjectId, ref:'Place'} 
  },
  ranking_in_place : Number })
  </code></pre>
  
  <p>Place is a reference to Place schema which has name, city, country etc. fields.</p>
  
  <p>I want to create a virtual for ranking_summary:</p>
  
  <pre><code>ItemSchema.virtual('ranking_summary').get(function() { 
      if(this.ranking_in_place &lt;= 5){
          if(this.ranking_in_place == 1){
              return "Most popular item" + " in " + this.location.place.name 
          }
      }
  })
  </code></pre>
  
  <p>I cannot get this.location.place.name value because this.location.place is a reference, and not populated. How can I access this value? </p>