text: const moogose = require('mongoose');
  const Schema = moogose.Schema;
  
  /**
   * 
   * @param user 提问人
   * @param replyState 回复的状态
   * @param issue      提出的问题
   * @param replyContent 回复的内容
   * @param article  提出问题的文章
   * @param author  回复的管理员
   * @param viewState 消息的查看状态
   * 
   */
  
  const replySchema = new Schema({
    user: {type: Schema.Types.ObjectId, ref: 'user', index: true},
    replyState: {type: Boolean, default: false},
    issue: String,
    replyContent: {type: String, default: ''},
    article : {type: Schema.Types.ObjectId, ref: 'article'},
    admin: {type: Schema.Types.ObjectId, ref: 'admin'},
    date: {type: Date, default: Date.now},
    viewState: {type: Boolean, default: false}
  })
  
  const Reply = moogose.model('reply', replySchema)
  
  module.exports = Reply