old_contents: 'use strict';
  
  /**
   * Module dependencies.
   */
  var mongoose = require('mongoose'),
    Schema = mongoose.Schema;
  
  /**
   * Storeroom Schema
   */
  var StoreroomSchema = new Schema({
    name: {
      type: String,
      default: '',
      required: 'Please fill Storeroom name',
      trim: true
    },
    created: {
      type: Date,
      default: Date.now
    },
    user: {
      type: Schema.ObjectId,
      ref: 'User'
    }
  });
  
  mongoose.model('Storeroom', StoreroomSchema);
  
new_contents: 'use strict';
  
  /**
   * Module dependencies.
   */
  var mongoose = require('mongoose'),
    Schema = mongoose.Schema;
  
  /**
   * Storeroom Schema
   */
  var StoreroomSchema = new Schema({
    name: {
      type: String,
      default: '',
      required: 'Please fill Storeroom name',
      trim: true
    },
    parent: {
      type: Schema.ObjectId,
      ref: 'Storeroom'
    },
    created: {
      type: Date,
      default: Date.now
    },
    user: {
      type: Schema.ObjectId,
      ref: 'User'
    }
  });
  
  mongoose.model('Storeroom', StoreroomSchema);
  
subject: add parent in storeroom-model