redmine/app/views/issue_relations/index.api.rsb

api.array :relations do
  @relations.each do |relation|
    api.relation do
      api.id relation.id
      api.issue_id relation.issue_from_id
      api.issue_to_id relation.issue_to_id
      api.relation_type relation.relation_type
      api.delay relation.delay
    end
  end
end