twitter/scalding — pull request #305 by tchklovski (2013-02-08 22:14:22+00:00)
Title: add "shuffle" method

Would be useful to have "shuffle" which ensures rows are in random
order -- so future `take` and `foldLeft` operations get random data
Looking for guidance on implementation:
- should reducers be implicit (so one calls shuffle(){ _.reducers(50) } ?)
- should refactor groupRandomly to rely on modified shuffleAux?
- should seed be implicit?
- does grouping by shard, as in groupRandomly guarantee that each
reducer gets one shard?