public IHttpActionResult Putcity(decimal id, city city)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            if (id != city.City_id)
            {
                return BadRequest();
            }

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

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

            return StatusCode(HttpStatusCode.NoContent);
        }
        public IHttpActionResult Postcity(city city)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            db.cities.Add(city);

            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateException)
            {
                if (cityExists(city.City_id))
                {
                    return Conflict();
                }
                else
                {
                    throw;
                }
            }

            return CreatedAtRoute("DefaultApi", new { id = city.City_id }, city);
        }