Rails Admin Sort By Relation Attribute

I got a rather old app using Rails Admin 0.4. I am not a guy so much good with magic and thus would need some help with Rails Admin configuration.

I am in need of sorting the list view of a model by a relation attribute. For example I got a setup like Exchange belongs_to :worker, :class_name => "Person", :foreign_key => "worker_id". I would like to sort it by the name attribute of the Person.

A bare installation sorts it by the #id of the person (worker_id in this case). I would like that to be #name in the Person class.

Stuff are as follows, though I doubt will be necessary to help.

RailsAdmin.config do |config|
  config.model ExchangeAndFee do
    list do
      field :created_at
      field :customer do
        searchable [{Person => :name}]
        queryable true
      end
      field :worker do
        searchable :workers_exchanges => :name
        queryable true
      end
      field :amount
      field :notes do
        label "Memo"
        formatted_value do
          bindings[:object].memo
        end
      end
    end
  end
end

Additional Details

• Rails 3
• Rails Admin 0.4
• App OSCurrency

Any help is highly appreciated.