fix limit being hard coded to 20

apps/threads.lua

@@ -85,8 +85,8 @@ app:get("thread", "/:slug", function(self)
       posts.thread_id = ?
     ORDER BY
       posts.created_at ASC
-    LIMIT 20 OFFSET ?
-  ]], thread.id, (self.page - 1) * posts_per_page)
+    LIMIT ? OFFSET ?
+  ]], thread.id, posts_per_page, (self.page - 1) * posts_per_page)
   self.topic = Topics:find(thread.topic_id)
   self.user = util.get_logged_in_user_or_transient(self)
   self.posts = posts