add timestamps to crocodoc_documents

Change-Id: Ib1226b0aed4be89456b5c8f2ca250318ec254b13
Reviewed-on: https://gerrit.instructure.com/33317
Reviewed-by: Simon Williams <simon@instructure.com>
QA-Review: Simon Williams <simon@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Cameron Matheson <cameron@instructure.com>

db/migrate/20140414230423_add_timestamps_to_crocodoc_documents.rb

@@ -0,0 +1,12 @@
+class AddTimestampsToCrocodocDocuments < ActiveRecord::Migration
+  tag :predeploy
+
+  def self.up
+    add_timestamps(:crocodoc_documents)
+  end
+
+  def self.down
+    remove_column :crocodoc_documents, :created_at
+    remove_column :crocodoc_documents, :updated_at
+  end
+end