fix for publication_author query with postgres
fix for publication_author query with postgres

required the :author_index adding to the group, as this is magically appending to the query because the scope(:order ... )

stuzart/seek,HITS-SDBV/seek,stuzart/seek,HITS-SDBV/seek,HITS-SDBV/seek,HITS-SDBV/seek,stuzart/seek