public IHttpActionResult Create(HomeworksOutputModel homeworksInfo)
        {
            if (!this.ModelState.IsValid)
            {
                return this.BadRequest(this.ModelState);
            }

            var newHomework = new Homework()
                                  {
                                      Id = homeworksInfo.Id,
                                      FilePath = homeworksInfo.FilePath,
                                      SentDateTime = homeworksInfo.SentDateTime
                                  };

            this.studentData.Homeworks.Add(newHomework);
            homeworksInfo.Id = newHomework.Id;
            return this.Ok(homeworksInfo);
        }
        public IHttpActionResult Update(HomeworksOutputModel homeworksInfo)
        {
            if (!this.ModelState.IsValid)
            {
                return this.BadRequest(this.ModelState);
            }

            var homeworkToUpdate = this.studentData.Homeworks.FirstOrDefault(hm => hm.Id == homeworksInfo.Id);

            if (homeworkToUpdate == null)
            {
                return this.BadRequest(NoSuchHomeWork);
            }

            homeworkToUpdate.FilePath = homeworksInfo.FilePath;
            homeworkToUpdate.SentDateTime = homeworksInfo.SentDateTime;

            this.studentData.SaveChanges();

            return this.Ok(homeworksInfo);
        }