Indexed DB + Promises

One of the top requests[1] we've received for future iterations of Indexed
DB is integration with ES Promises. While this initially seems
straightforward ("aren't requests just promises?") the devil is in the
details - events vs. microtasks, exceptions vs. rejections, automatic
commits, etc.

After some noodling and some very helpful initial feedback, I've got what I
think is a minimal proposal for incrementally evolving (i.e. not replacing)
the Indexed DB API with some promise-friendly affordances, written up here:

https://github.com/inexorabletash/indexeddb-promises

I'd appreciate feedback from the WebApps community either here or in that
repo's issue tracker.

[1] https://www.w3.org/2008/webapps/wiki/IndexedDatabaseFeatures