old_contents: /**
   * Created by Songzhou Yang on 12/11/2016.
   */
  
  const TeachingInfo = require('../models/teaching_info')
  
  const getTeachingInfo = async() => {
    const _info = await TeachingInfo.findOne({})
    const info = {}
    info.time = _info.time
    info.currentSemester = _info.currentSemester.toObject()
    info.currentTeachingWeek = _info.currentTeachingWeek.toObject()
    info.nextSemester = _info.nextSemester.toObject()
    return info
  }
  
  module.exports = getTeachingInfo
  
new_contents: /**
   * Created by Songzhou Yang on 12/11/2016.
   */
  
  const TeachingInfo = require('../models/teaching_info')
  
  const getTeachingInfo = async() => {
    const _info = await TeachingInfo.findOne({})
    const info = {}
    info.updateTime = _info.time
    info.currentSemester = _info.currentSemester.toObject()
    info.currentTeachingWeek = _info.currentTeachingWeek.toObject()
    info.nextSemester = _info.nextSemester.toObject()
    return info
  }
  
  module.exports = getTeachingInfo
  
subject: modify return msg