add updated at to students

admin/app/admin/students.rb

@@ -6,12 +6,15 @@ ActiveAdmin.register JamRuby::User, :as => 'Students' do
   config.batch_actions = false
   config.per_page = 100
   config.paginate = true
-  config.filters = false
+  config.filters = true
 
   def   booked_anything(scope)
     scope.joins(:student_lesson_bookings).where('lesson_bookings.active = true').uniq
   end
 
+  filter :jamuser_full_name_or_email_cont, label: 'Name Or Email', as: :string
+  filter :school, label: 'School'
+
   scope("Default", default: true) { |scope| scope.where('is_a_student = true OR jamclass_credits > 0 OR ((select count(id) from lesson_bookings where lesson_bookings.user_id = users.id) > 0)').order('users.ready_for_session_at IS NULL DESC') }
 
   index do
@@ -50,6 +53,7 @@ ActiveAdmin.register JamRuby::User, :as => 'Students' do
         user.school.name
       end
     end
+    column :updated_at
   end
 
   member_action :mark_session_ready, :method => :get do