Amends rake task to index statistics announcements
Amends rake task to index statistics announcements

The current rake task reindexes all statistics announcements.
But once a statistic has been released, its announcement is no
longer presented by the finder. This task now reindexes only the
stats announcements which have an unpublished publication.

alphagov/whitehall,alphagov/whitehall,alphagov/whitehall,alphagov/whitehall