Idea: ACID transactions support

[rushmorem]

http://rystsov.info/2012/09/01/cas.html
http://rystsov.info/2016/03/02/cross-shard-txs.html
https://github.com/rystsov/mongodb-transaction-example
https://docs.mongodb.com/manual/tutorial/perform-two-phase-commits/
https://www.cockroachlabs.com/blog/how-cockroachdb-distributes-atomic-transactions/
https://github.com/cockroachdb/cockroach/blob/master/docs/design.md#lock-free-distributed-transactions

The API would possibly look like:-

r.transaction(|txn| {
  // Multi-document ReQL queries here
})

[zicklag]

That would be completely awesome to have. 😃