app/serializers/board_serializer.rb
class BoardSerializer
include TalkSerializer
include EmbeddedAttributes
all_attributes
attribute :latest_discussion
can_filter_by :subject_default
can_sort_by :id, :position, :last_comment_created_at
embed_attributes_from :project
self.default_sort = 'position,-last_comment_created_at'
self.preloads = [:latest_discussion]
self.eager_loads = [:project, :parent]
def latest_discussion
DiscussionSerializer.as_json model.latest_discussion
end
end