article.rb

ActiveAdmin.register Article do
  index do
    selectable_column
    id_column
    column :name, :sortable => :name do |resource|
      editable_text_column resource, :name
    end
    column 'Type', :sortable => :article_type do |resource|
      column_select(resource, :article_type, ["News", "Story", "Case Study", "Business"])
    end
    column :created_at
    column :updated_at
    default_actions
  end
end