activeadmin を更新した後、管理パネルにアクセスできません。管理ユーザーは admin_users というテーブルに保存されています。
NoMethodError in Admin::DashboardController#index
undefined method `authenticate_admin_user!' for #Admin::DashboardController:0x007fe46c3d99d0
Rails.root: /Users/jianbo/Documents/Aptana Studio 3 Workspace/iv
Application Trace | Framework Trace | Full Trace
activeadmin (0.6.2) lib/active_admin/base_controller.rb:40:in authenticate_active_admin_user'
activesupport (3.2.15) lib/active_support/callbacks.rb:474:inblock in run_3994836635519503653__process_action__2211030722258422070__callbacks'
activesupport (3.2.15) lib/active_support/callbacks.rb:215:in `block in conditionalcallback_around_863'