die() if there's no "stories_id" query parameter
die() if there's no "stories_id" query parameter

It's too easy to mix up /stories/corenlp/<...> and /stories/corenlp?stories_id=<...>

berkmancenter/mediacloud,berkmancenter/mediacloud,berkmancenter/mediacloud,berkmancenter/mediacloud,berkmancenter/mediacloud