hotfix school

app/controllers/admin/education/schools_controller.rb

@@ -47,7 +47,7 @@ class Admin::Education::SchoolsController < Admin::Education::ApplicationControl
 
   def destroy
     @school.destroy_and_sync
-    redirect_to admin_university_schools_url, notice: t('admin.successfully_destroyed_html', model: @school.to_s)
+    redirect_to admin_education_schools_url, notice: t('admin.successfully_destroyed_html', model: @school.to_s)
   end
 
   private

app/models/education/school/with_alumni.rb

@@ -4,7 +4,8 @@ module Education::School::WithAlumni
   included do
 
       has_many    :education_cohorts,
-                  class_name: 'Education::Cohort'
+                  class_name: 'Education::Cohort',
+                  dependent: :destroy
                   alias_attribute :cohorts, :education_cohorts
 
       has_many    :alumni, -> { distinct },