public async Task<IHttpActionResult> PostPhotoResistance(PhotoResistance photoResistance)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }
            if(photoResistance.CollectionTime == null)
            {
                photoResistance.CollectionTime = DateTime.UtcNow;
            }
            
            db.PhotoResistances.Add(photoResistance);

            try
            {
                await db.SaveChangesAsync();
            }
            catch (DbUpdateException)
            {
                if (PhotoResistanceExists(photoResistance.Id))
                {
                    return Conflict();
                }
                else
                {
                    throw;
                }
            }

            return CreatedAtRoute("DefaultApi", new { id = photoResistance.Id }, photoResistance);
        }
        public async Task<IHttpActionResult> PutPhotoResistance(int id, PhotoResistance photoResistance)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            if (id != photoResistance.Id)
            {
                return BadRequest();
            }

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

            try
            {
                await db.SaveChangesAsync();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!PhotoResistanceExists(id))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }

            return StatusCode(HttpStatusCode.NoContent);
        }