public async Task <ActionResult> DeleteFavouriteTrainer(int trainerId)
        {
            var userId = User.FindFirstValue(ClaimTypes.NameIdentifier);

            try
            {
                await _favouriteService.DeleteFavouriteTrainer(trainerId, userId);

                return(Ok());
            }
            catch (ArgumentNullException exception)
            {
                return(BadRequest(exception.Message));
            }
            catch (Exception exception)
            {
                return(BadRequest(exception.Message));
            }
        }