+db/migrate/*_creative_commons_v??_licenses_attributes.rb
+db/migrate/*_pettan_commons_v??_licenses_attributes.rb
+db/migrate/*_pettan_protected_v??_licenses_attributes.rb
+db/migrate/*_pettan_public_v??_licenses_attributes.rb
+db/migrate/*_public_domain_v??_licenses_attributes.rb
+db/migrate/*_unknown_v??_licenses_attributes.rb