activeadmin has_many new model label button and I18n

active_admin.rb

# config/initializer/active_admin.rb
ActiveAdmin.setup do |config|
  # == Site Title
  #
  # Set the title that is displayed on the main layout
  # for each of the active admin pages.
  ...
end

ActiveAdmin::FormBuilder.class_eval do
  def has_many(association, options = {}, &block)
      options = { :for => association }.merge(options)
      options[:class] ||= ""
      options[:class] << "inputs has_many_fields"

      # Add Delete Links
      form_block = proc do |has_many_form|
        block.call(has_many_form) + if has_many_form.object.new_record?
                                      template.content_tag :li do
                                        template.link_to I18n.t('active_admin.has_many_delete'), "#", :onclick => "$(this).closest('.has_many_fields').remove(); return false;", :class => "button"
                                      end
                                    else
                                    end
      end

      content = with_new_form_buffer do
        template.content_tag :div, :class => "has_many #{association}" do
          form_buffers.last << template.content_tag(:h3, association.to_s.titlecase)
          inputs options, &form_block

          # Capture the ADD JS
          js = with_new_form_buffer do
            inputs_for_nested_attributes  :for => [association, object.class.reflect_on_association(association).klass.new],
                                          :class => "inputs has_many_fields",
                                          :for_options => {
                                            :child_index => "NEW_RECORD"
                                          }, &form_block
          end

          js = template.escape_javascript(js)
          # replace next line
          #js = template.link_to I18n.t('active_admin.has_many_new', :model => association.to_s.singularize.titlecase), "#", :onclick => "$(this).before('#{js}'.replace(/NEW_RECORD/g, new Date().getTime())); return false;", :class => "button"
          # with this new line
          js = template.link_to I18n.t('active_admin.has_many_new', :model => I18n.t(association.to_s.singularize)),
            "#", :onclick => "$(this).before('#{js}'.replace(/NEW_RECORD/g, new Date().getTime())); return false;", :class => "button"

          form_buffers.last << js.html_safe
        end
      end
      form_buffers.last << content.html_safe
    end
end

insert this code in the very bottom of config/initializer/active_admin.rb
the trick is:
:model => I18n.t(association.to_s.singularize))

Then in your I18n file set the translation

Good luck!!