#22 完了

backend/app/models/user.rb

@@ -17,6 +17,6 @@ class User < ApplicationRecord
   has_many :updated_wiki_pages, class_name: 'WikiPage', foreign_key: 'updated_user_id', dependent: :nullify
 
   def viewed? post
-    user_post_views.exists? post_id: post.id, viewed: true
+    user_post_views.exists? post_id: post.id
   end
 end