Method write

ch4/BoardController2.java:45–50

(Model m)

    }

    @GetMapping("/write")
    public String write(Model m) {
        m.addAttribute("mode", "new");

        return "board";
    }

    @PostMapping("/write") // insert니까 delete인 remove하고 동일
    public String write(BoardDto boardDto, RedirectAttributes rattr, Model m, HttpSession session) {