Import Model::transaction from Shopify
Add docs for Model::transaction
Move Batman.Transaction to its own file
add tests and implement TransactionAssociationSet
remove comments and leftover do
make transaction set extend Set
load empty TransactionAssociationSets for empty transactions
define .length on TransactionAssociationSet
TransactionAssociationSet tracks removed items, too
If ::transaction triggers a load on a hasMany, those items should be added to the transaction when they're loaded
add test for transaction on polymorphic has many
implement and test association reflection
associations can opt out of transaction with includeInTransaction: false
add developer warning for mutable objects
check for {} objects only
oops
fix for looping applyChanges
beef up docs for transaction, move validators to own file
better names and better organization in TransactionAssociationSet
clean up association reflection, add tests for missing associations, add docs