text: var mongoose = require('mongoose');
  var Schema = mongoose.Schema;
  
  var Tag_Schema = new Schema({
      tagName: { type: String, required: true, unique: true },
      dateTime_create: { type: Date, default: Date.now },
      dateTime_edit: { type: Date, default: Date.now }
  });
  
  module.exports = mongoose.model('Tag', Tag_Schema);
  
  // {
  //     "_id": "_id","tagName" : "tagName","dateTime_create" : "dateTime_create"
  // }