Add the possibility to disable weekly email notifications (instructeur) && rename the column email_notifications_enabled to daily_email_notification_enabled

db/migrate/20200210100938_add_weekly_email_notifications_to_assign_tos.rb

@@ -0,0 +1,5 @@
+class AddWeeklyEmailNotificationsToAssignTos < ActiveRecord::Migration[5.2]
+  def change
+    add_column :assign_tos, :weekly_email_notifications_enabled, :boolean, default: true, null: false
+  end
+end