Document new attribute and caveats for sqlite compound queries.
Document new attribute and caveats for sqlite compound queries.

jnovinger/peewee,wenxer/peewee,bopo/peewee,zhang625272514/peewee,Dipsomaniac/peewee,wenxer/peewee,py4a/peewee,ronyb29/peewee,new-xiaji/peewee,jarrahwu/peewee,fuzeman/peewee,coreos/peewee,bopo/peewee,coreos/peewee,teserak/peewee,stas/peewee,jarrahwu/peewee,new-xiaji/peewee,coleifer/peewee,Sunzhifeng/peewee,bopo/peewee,jarrahwu/peewee,Sunzhifeng/peewee,Dipsomaniac/peewee,Dipsomaniac/peewee,zhang625272514/peewee,jnovinger/peewee,Sunzhifeng/peewee,coleifer/peewee,fuzeman/peewee,zhang625272514/peewee,softside/peewee,ghukill/peewee,mackjoner/peewee,new-xiaji/peewee,coleifer/peewee,lez/peewee,coreos/peewee