show page date fix to postdate

app/controllers/announcements_controller.rb

@@ -116,7 +116,7 @@ class AnnouncementsController < ApplicationController
       "data" => {
         "title" => announcement.title,
         "update_user" => update_user,
-        "updated_at" => announcement.updated_at.strftime('%Y-%m-%d %H:%M'),
+        "updated_at" => announcement.postdate.strftime('%Y-%m-%d %H:%M'),
         "body" =>announcement.text,
         "image" => announcement.image.url
       },