add framework for post update pushes to pubsub

db/migrate/20160820003534_create_post_updates.rb

@@ -0,0 +1,9 @@
+class CreatePostUpdates < ActiveRecord::Migration
+  def up
+    execute "create unlogged table post_updates ( post_id integer, constraint unique_post_id unique(post_id) )"
+  end
+
+  def down
+    execute "drop table post_updates"
+  end
+end