@PostMapping("/rent")
    public ResponseEntity<HttpStatus> bikeRent(@RequestBody BikeRentDTO bikeRentDTO){
        Optional<Stand> optionalStand = standRepository.findById(bikeRentDTO.getStandId());
        Optional<Bike> optionalBike = bikeRepository.findById(bikeRentDTO.getBikeId());
        if (optionalStand.isPresent() && optionalBike.isPresent()){
            Bike bike = optionalBike.get();
            Stand stand = optionalStand.get();
            if (stand.getBike().getId() == bike.getId()){
                stand.setBike(null);
                stand.setIsAvailable(Stand.available.YES);
                bike.setRented(Bike.isRented.YES);
                standRepository.save(stand);
                bikeRepository.save(bike);
                return new ResponseEntity<>(HttpStatus.OK);
            }
        }
        return new ResponseEntity<>(HttpStatus.BAD_REQUEST);
    }