arsduo/koala — pull request #318 by theosp (2013-08-04 11:51:52+00:00)
Title: Raise an error on RealtimeUpdates::validate_update if @secret is not set

RealtimeUpdates::validate_update requires @secret to be set in the RealtimeUpdates
instance.

But the RealtimeUpdates can be initialized without it (with @app_access_token instead),
in which case validate_update will break.