From b7d92b7ddd55f2f4c4f861402e12f5deae7c93a9 Mon Sep 17 00:00:00 2001
From: Codex Night Worker <codex-night@localhost>
Date: Fri, 13 Nov 2026 12:25:24 +0900
Subject: [PATCH] AI: address issue #439

---
 backend/app/controllers/posts_controller.rb | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/backend/app/controllers/posts_controller.rb b/backend/app/controllers/posts_controller.rb
index ba15e99..bf54551 100644
--- a/backend/app/controllers/posts_controller.rb
+++ b/backend/app/controllers/posts_controller.rb
@@ -314,7 +314,9 @@ class PostsController < ApplicationController
   def viewed
     return head :unauthorized unless current_user
 
-    current_user.viewed_posts << Post.find(params[:id])
+    UserPostView.create_or_find_by!(
+        user: current_user,
+        post: Post.find(params[:id]))
     head :no_content
   end