Add Cache-Control for authenticated pages

cmd/boardvoting/middleware.go

@@ -88,6 +88,8 @@ func (app *application) tryAuthenticate(next http.Handler) http.Handler {
 			return
 		}
 
+		w.Header().Add("Cache-Control", "no-store")
+
 		next.ServeHTTP(w, r.WithContext(context.WithValue(r.Context(), ctxUser, user)))
 	})
 }