text: var mongoose = require('mongoose');
  var Schema = mongoose.Schema;
  var ObjectId = Schema.ObjectId;
  	
  var TopicSchema = new Schema({
  	title: { type: String },
  	content: { type: String },
  	author_id: { type: ObjectId },
  	top: { type: Boolean, default: false },
  	reply_count: { type: Number, default: 0 },
  	visit_count: { type: Number, default: 0 },
  	collect_count: { type: Number, default: 0 },
  	create_at: { type: Date, default: Date.now },
  	update_at: { type: Date, default: Date.now },
  	last_reply: { type: ObjectId },
  	last_reply_at: { type: Date, default: Date.now },
  	content_is_html: { type: Boolean }
  });
  
  mongoose.model('Topic', TopicSchema);
  