Почему не сохраняются изменения в БД mongoose?

seal:marat-auth-api-service/ $ curl --data "username=marataziat&&password=gfar" localhost:4001/creditals                                         [18:00:05]
{"password":true,"key":"157f6d16-7ee5-4985-a7b4-c1fa78685641"}%

> db.users.find()
{ "_id" : ObjectId("5a9d103b01a1c09cc50c481b"), "firstname" : "marat", "secondname" : "mkhitaryan", "username" : "marataziat", "password" : "gfar", "sessionkey" : "@sdas", "logindate" : 20 }