add translation

lib/mv_web/locale_controller.ex

@@ -4,6 +4,8 @@ defmodule MvWeb.LocaleController do
   def set_locale(conn, %{"locale" => locale}) do
     conn
     |> put_session(:locale, locale)
+    # Store locale in a cookie that persists beyond the session
+    |> put_resp_cookie("locale", locale, max_age: 365 * 24 * 60 * 60, same_site: "Lax")
     |> redirect(to: get_referer(conn) || "/")
   end