public ActionResult <IEnumerable <PlanetDto> > GetPlanetsForFilm(int filmId)
        {
            var list = new List <PlanetDto>();

            if (!_starWarsRepository.FilmExists(filmId))
            {
                return(NotFound());
            }

            var planets = _starWarsRepository.GetPlanetsForFilm(filmId);

            foreach (var filmPlanet in planets)
            {
                list.Add(new PlanetDto()
                {
                    Id             = filmPlanet.FilmId,
                    Name           = filmPlanet.Planet.Name,
                    Diameter       = filmPlanet.Planet.Diameter,
                    RotationPeriod = filmPlanet.Planet.RotationPeriod,
                    FilmId         = filmPlanet.FilmId
                });
            }

            return(Ok(list));
        }