text: var mongoose = require('mongoose');
  
  // 定义Schema
  UserSchema = new mongoose.Schema({
    username: {// 真实姓名
      type: String,
      required: true
    },
    password: { // 密码
      type: String,
      required: true
    }
  });
  
  // 定义Model
  var UserModel = mongoose.model('User', UserSchema);
  
  // 暴露接口
  module.exports = UserModel;
  