Schema is now a service. The initializer is no longer necessary. Add a
schema to app/services/m3-schema.js. For convenience you can extend a
default schema from ember-m3/services/schema.
SchemaManager is now a service, which requires schema initialization to happen in an instance
initializer or equivalent. The name of the service is m3-schema-manager.
It is now possible for computeAttributeReference to return an array of {id, type} pairs. This is treated as a plain array of references (not a RecordArray).
Expect isAttributeArrayReference, and computeNestedModel to behave similarly in the future.