class ActiveModel::Serializer

def embedded_in_root_associations
  associations = self.class._associations
  included_associations = filter(associations.keys)
  associations.each_with_object({}) do |(name, association), hash|
    if included_associations.include? name
      if association.embed_in_root?
        association_serializer = build_serializer(association)
        hash.merge! association_serializer.embedded_in_root_associations
        serialized_data = association_serializer.serializable_object
        key = association.root_key
        if hash.has_key?(key)
          hash[key].concat(serialized_data).uniq!
        else
          hash[key] = serialized_data
        end
      end
    end
  end
end