public IHttpActionResult PostAccessCode(AccessCode accessCode)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            db.AccessCodes.Add(accessCode);

            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateException)
            {
                if (AccessCodeExists(accessCode.Code))
                {
                    return Conflict();
                }
                else
                {
                    throw;
                }
            }

            return CreatedAtRoute("DefaultApi", new { id = accessCode.Code }, accessCode);
        }
        public IHttpActionResult PutAccessCode(string id, AccessCode accessCode)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            if (id != accessCode.Code)
            {
                return BadRequest();
            }

            db.Entry(accessCode).State = EntityState.Modified;

            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!AccessCodeExists(id))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }

            return StatusCode(HttpStatusCode.NoContent);
        }