Change feeds_layers table to subscriptions

app/models/post.rb

@@ -42,15 +42,15 @@ class Post < ActiveRecord::Base
         ( -- Subquery returns a list of post_ids for posts on this layer
           SELECT p.id
 
-          FROM feeds_layers fl
+          FROM subscriptions s
           
           INNER JOIN feeds f
-          ON fl.feed_id = f.id
+          ON s.feed_id = f.id
 
           INNER JOIN posts p
           ON p.feed_id = f.id
 
-          WHERE fl.layer_id = #{layer_id}
+          WHERE s.layer_id = #{layer_id}
         )
           
         AND