private IHttpActionResult ValidatePicture(PictureModel p)
        {
            var dbContext = new ApplicationDbContext();

            if (p.ApplicationUserId == null || !dbContext.Users.Any(x => x.Id == p.ApplicationUserId))
            {
                return BadRequest("ApplicationUserId NOT FOUND");
            }

            if (p.CategoryId == null || !dbContext.Categories.Any(x => x.CategoryId == p.CategoryId))
            {
                return BadRequest("CategoryId NOT FOUND");
            }

            if (p.Link == null || !p.Link.StartsWith("https://"))
            {
                return BadRequest("Invalid Url");

            }

            return Ok();
        }
        public IHttpActionResult PutPicture(PictureModel picture)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            // TODO Add validations
            this.data.Pictures.Find(picture.Id).Link = picture.Link;

            try
            {
                this.data.SaveChanges();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!PictureExists(picture.Id))
                {
                    return NotFound();
                }
                else
                {
                    throw new ArgumentException("The picture Id wasn't valid");
                }
            }

            return StatusCode(HttpStatusCode.NoContent);
        }
        public IHttpActionResult PostPicture(PictureModel p)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            this.data.Pictures
                     .Add(new Picture()
                     {
                         CategoryId = p.CategoryId,
                         ApplicationUserId = p.ApplicationUserId,
                         Link = p.Link
                     });
            
            this.data.SaveChanges();
            return CreatedAtRoute("DefaultApi", new { id = p.Id }, p);
        }