OGM-420 Making read preference configurable via a configuration property
OGM-420 Making the read preference configurable programmatically
OGM-420 Making the read preference configurable via annotations
OGM-420 Applying configured read preference for datastore operations
OGM-420 Making AssociationStorageStrategy an enum to avoid repeated instantiations
OGM-420 Updating reference guide
OGM-342 Some doc improvements
OGM-420 Addressing review remarks