Deep Nesting active_admin

deep_nesting.rb

 form do |f|
    f.inputs "Challenge" do
      f.input :name
      f.input :about
      f.input :starts
      f.input :ends
    end

    f.inputs do
      f.has_many :time_sets do |time_set|
        time_set.input :name
        time_set.has_many :participants do |participant|
          participant.input :first_name
          participant.input :last_name
          participant.input :email
          participant.input :birth_year
          participant.input :team
          participant.input :qualification
        end
      end
    end

    f.buttons
  end