text: // app/models/photo.js
  // load dependencies
  var mongoose = require('mongoose')
      , Schema = mongoose.Schema;
  
  // define the model schema
  var photoSchema = mongoose.Schema({
      _id: String,
      ref: { type: String, ref: 'Fanpage' },
      source: String,
      time: Date,
      cdn: String,
      name: String,
      album_id: { type: String, ref: 'Album' },
  });
  
  // export photo model
  module.exports = mongoose.model('Photo', photoSchema);