delete events without submitter

app/models/event.rb

@@ -13,7 +13,7 @@ class Event < ActiveRecord::Base
   has_many :event_attachments, dependent: :destroy
   has_many :users, through: :event_users
   has_many :speakers, through: :event_users, source: :user
-  has_many :votes
+  has_many :votes, dependent: :destroy
   has_many :voters, through: :votes, source: :user
   has_many :commercials, as: :commercialable, dependent: :destroy
   belongs_to :event_type

db/migrate/20140717110124_delete_events_without_user.rb

@@ -0,0 +1,16 @@
+class DeleteEventsWithoutUser < ActiveRecord::Migration
+
+  def up
+    # User deletion without all the proper dependent: :destroy options might have left
+    # Events without a submitter (event_user association is deleted, but Event itslef is not)
+    Event.all.each do |event|
+      if event.users.blank?
+        event.destroy
+      end
+    end
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration, 'Cannot reverse migration. Events deleted cannot be re-created'
+  end
+end