This was released on April 27. Old news.
I think there's now too much going on and too few people reading /newest for the HN front page to be a resaonably accurate representation of the big stories if a key Rails release didn't even make it at the time :) Seen quite a few similar instances as well. (The real issue IMHO is not enough exposure of or encouragement to visit /newest, so it's pot luck if links get seen.)