public void CreateNewCandidate(TodoStudent stu)
        {
            stu.DefaultToNone();
            var collection = db.GetCollection <BsonDocument>("candidate");

            var doc = stu.UserToBson();

            collection.InsertOne(doc);
        }
        //-------------------------------------------UPDATE METHODS-------------------------------------------------------------------

        public TodoStudent UpdateUserInfo(string email, TodoStudent newStu)
        {
            TodoStudent stu = GetUserByEmail(email);

            newStu = newStu.DefaultToExisting(stu);
            var collection = db.GetCollection <BsonDocument>("candidate");
            var doc        = newStu.UserToBson();
            var search     = new BsonDocument("Email", email);

            BsonDocument found;

            found = collection.Find(search).First();
            collection.ReplaceOne(found, doc);
            return(newStu);
        }