[HttpGet] // GET: heroes
        public async Task <IActionResult> GetAll()
        {
            var query  = new GetAllHeroesQuery();
            var result = await _mediator.Send(query);

            return(Ok(result));
        }
        public async Task <IEnumerable <HeroDto> > Handle(GetAllHeroesQuery request, CancellationToken cancellationToken)
        {
            var heroes = await _heroRepository.GetAllHeroesAsync();

            return(_mapper.Map <IEnumerable <HeroDto> >(heroes));
        }