@Controller
@RequestMapping("/shop")
public class AppController {

    @Autowired
    private UserService userService;

    @GetMapping
    public String authPage() {
        return "authPage";
    }

    @PostMapping("/home")
    public String greeting(@RequestParam(name = "login") String login,
                           @RequestParam(name = "pass") String password, Model model) {
        Users user = userService.findUserByLoginPass(login, password);
        if (user != null) {
            model.addAttribute("user", user);
            return "index";
        } else {
            return "error";
        }
    }
}