text: var mongodb = require('../models/mongodb');
  var Schema = mongodb.mongoose.Schema;
  
  var postSchema = new Schema({
      title: String,
      time: {
          type: Date,
          index: true,
          default: Date.now()
      },
      content: String,
      summary: String,
      tags: [String],
      url: {
          type: String,
          unique: true
      },
      catalog: {
          type: Schema.Types.ObjectId,
          ref: 'catalogs'
      },
      isPage: {
          type: Boolean,
          index: true
      }
  });
  
  var posts = mongodb.mongoose.model('posts', postSchema);
  module.exports = posts;