fix forum last page

app/models/forum_post.rb

@@ -120,7 +120,7 @@ class ForumPost < ActiveRecord::Base
   end
 
   def forum_topic_page
-    ((ForumPost.where("topic_id = ? and created_at <= ?", topic_id, created_at).count) / Danbooru.config.posts_per_page.to_f).ceil
+    ((ForumPost.where("topic_id = ? and created_at <= ?", topic_id, created_at).count) / CurrentUser.user.per_page.to_f).ceil
   end
 
   def is_original_post?

app/models/forum_topic.rb

@@ -56,7 +56,7 @@ class ForumTopic < ActiveRecord::Base
   end
 
   def last_page
-    (posts.count / Danbooru.config.posts_per_page.to_f).ceil
+    (posts.count / CurrentUser.user.per_page.to_f).ceil
   end
 
   def presenter(forum_posts)