remove uniqueness constraint on postupdates

db/migrate/20160822230752_remove_uniqueness_constraint_on_post_updates.rb

@@ -0,0 +1,8 @@
+class RemoveUniquenessConstraintOnPostUpdates < ActiveRecord::Migration
+  def up
+    execute "alter table post_updates drop constraint unique_post_id"
+  end
+
+  def down
+  end
+end