New specs for in-memory one-to-many associations
New specs for in-memory one-to-many associations

Related to #488:
http://wm.lighthouseapp.com/projects/4819/tickets/488

joevandyk/dm-core,engineyard/dm-core,tpitale/dm-core,tillsc/dm-core,ar-dm/ardm-core,datamapper/dm-core,alloy/dm-core