Handle translations with Globalize3 in Active Admin with Rails 4

event.rb

#app/models/event.rb

class Event < ActiveRecord::Base
  translates :title, :description, :summary
  has_many :event_translations
  accepts_nested_attributes_for :event_translations, :allow_destroy => true
end

event_translation.rb

#app/models/event_translation.rb

class EventTranslation < ActiveRecord::Base
  belongs_to :event
  validates_uniqueness_of :locale, :scope => :event_id
end

events.rb

#app/admin/events.rb


ActiveAdmin.register Event do
        params.permit project: [:date, :event_translations_attributes => [:title, :description, :summary, :locale, :id]]
  
  index do
    column :title
    column :description
    column :summary
    default_actions
  end

  form do |f|
    f.inputs :event do
      f.input :date, :as => :datepicker
    end

    f.inputs :traductions do
      f.has_many :event_translations do |g|
        g.input :locale, :as => :select, :collection => I18n.available_locales
        g.input :title
        g.input :description
        g.input :summary
      end
    end
    f.actions
  end

end