Extract id_key to a method
serialize_ids doesn't use source serializer and it's object
Move if object to the top
Save result of calling associated_object in a local var
Associations doesn't depend on the source serializer anymore :)
source_serializer_options => serializer_options
Remove unused variable
Use a third argument to pass serializer_options
Add default_embed_options
Rename opts to klass_options
Use the readers instead of accessing the ivar directly
Associations::Config is now Associations::Base
Move duplicated code to the Base class
Rename associated_object to object
Use private instead of protected, we don't use explicit receivers
Reorder methods
key method is defined on subclasses
Initialize things in the initialize method and define readers
Use == || == instead of include?
Move key method to the base class