run UseAssetUserAccessLastAccess as a delayed job

this table, it is large

test plan: run the migration, verify a job is just created. run the job,
verify it updates null last_access rows as expected.

Change-Id: Id134d6795c8eef76181c20f5e3c0920dd51dda21
Reviewed-on: https://gerrit.instructure.com/9192
Reviewed-by: Cody Cutrer <cody@instructure.com>
Tested-by: Hudson <hudson@instructure.com>

db/migrate/20120221220828_use_asset_user_access_last_access.rb

@@ -2,7 +2,7 @@ class UseAssetUserAccessLastAccess < ActiveRecord::Migration
   tag :postdeploy
 
   def self.up
-    AssetUserAccess.update_all("last_access = updated_at", "last_access is null")
+    DataFixup::UseAssetUserAccessLastAccess.send_later_if_production(:run)
   end
 
   def self.down

lib/data_fixup/use_asset_user_access_last_access.rb

@@ -0,0 +1,7 @@
+module DataFixup::UseAssetUserAccessLastAccess
+
+  def self.run
+    AssetUserAccess.update_all("last_access = updated_at", "last_access is null")
+  end
+
+end