Update dummy app to test against ActiveAdmin 0.6.6
Update dummy app to test against ActiveAdmin 0.6.6

hotvulcan/activeadmin-sortable-tree,hotvulcan/activeadmin-sortable-tree,zorab47/activeadmin-sortable-tree,hotvulcan/activeadmin-sortable-tree,zorab47/active_admin-sortable_tree,zorab47/activeadmin-sortable-tree,zorab47/active_admin-sortable_tree,zorab47/activeadmin-sortable-tree,zorab47/active_admin-sortable_tree