auto_round gone from DoubleField
Ah. Apparently auto_round was only intended (and meaningful) for DecimalFields. 

Starting from 2.2.0 peewee now complains about the superfluous attribute; something that it didn't before, so our upgrade failed.

Can someone confirm this?
 Yes that is correct.
 Sorry for the inconvenience, I refactored a lot of Field code, including cleaning up the attributes.
 Np, just caused us to clean up our code.

During upgrade from 2.17 to 2.2.0, auto_round vanished from DoubleField

Is that a bug, or is there a migration necessary? If the latter, there's a notice missing in the docs.
