add first draft for session handling

site_admin.go

@@ -20,6 +20,10 @@ func NewAdminPages() *AdminPages {
 }
 
 func (a *AdminPages) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+  cookie, _ := r.Cookie("sess")
+  if cookie == nil && r.URL.Path != "/admin/login" {
+    http.Redirect(w, r, "/admin/login", http.StatusFound)
+  }
   a.router.ServeHTTP(w, r)
 }