Add a picture format for conference tickets

db/migrate/20171130172334_rebuild_conference_pictures.rb

@@ -0,0 +1,9 @@
+class RebuildConferencePictures < ActiveRecord::Migration
+  def up
+    Conference.all.each do |conference|
+      conference.picture.recreate_versions!
+    end
+  end
+
+  def down; end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20171118113113) do
+ActiveRecord::Schema.define(version: 20171130172334) do
 
   create_table "ahoy_events", force: :cascade do |t|
     t.integer  "visit_id"