let userSchema = new mongoose.Schema({
username: {type: String, required: true},
  email: {type: String, required: true, index: {unique: true}},
  joinDate: {type: Date, default: Date.now},
  clips: [clipSchema],
  hash: {type: String},
  salt: {type: String}
})

userSchema.methods.setPassword = (password) => {
  this.salt = crypto.randomBytes(32).toString('hex')
  this.hash = crypto.pbkdf2Sync(password, this.salt, 100000, 512, 'sha512').toString('hex')
}

let user = new User()

user.username = req.body.username
user.email = req.body.email
user.setPassword(req.body.password)

user.save((err) => {
  if (err) {
    sendJsonResponse(res, 404, err)
  } else {
    let token = user.generateJwt()
    sendJsonResponse(res, 200, { 'token': token })
  }
})

{
 "_id" : ObjectId("576338b363bb7df7024c044b"),
 "email" : "boss@potato.com",
 "username" : "Bob",
 "clips" : [ ],
 "joinDate" : ISODate("2016-06-16T23:39:31.825Z"),
 "__v" : 0
}