old_contents: var mongoose     = require('mongoose');
  var Schema       = mongoose.Schema;
  
  var SurveyVoteSchema   = new Schema(
  {
      created : {type : Date, default : Date.now},
      lastEdited : {type : Date, default : Date.now},
      value : {type: mongoose.Schema.Types.ObjectId, ref : "SurveyItem"},
      user : {type: mongoose.Schema.Types.ObjectId, ref : "User"}
  });
  
  module.exports = mongoose.model('SurveyVote', SurveyVoteSchema);
  
new_contents: var mongoose     = require('mongoose');
  var Schema       = mongoose.Schema;
  
  var SurveyVoteSchema   = new Schema(
  {
      created : {type : Date, default : Date.now},
      lastEdited : {type : Date, default : Date.now},
      survey : {type: mongoose.Schema.Types.ObjectId, ref : "Survey"},
      value : {type: mongoose.Schema.Types.ObjectId, ref : "SurveyItem"},
      user : {type: mongoose.Schema.Types.ObjectId, ref : "User"}
  });
  
  module.exports = mongoose.model('SurveyVote', SurveyVoteSchema);
  
subject: Add SurveyVote#Survey field