diff --git a/db/post_migrate/20181012123001_drop_group_locked_trust_level_from_user.rb b/db/post_migrate/20181012123001_drop_group_locked_trust_level_from_user.rb
index 0092d77e254..1db54582345 100644
--- a/db/post_migrate/20181012123001_drop_group_locked_trust_level_from_user.rb
+++ b/db/post_migrate/20181012123001_drop_group_locked_trust_level_from_user.rb
@@ -1,3 +1,5 @@
+require 'migration/column_dropper'
+
 class DropGroupLockedTrustLevelFromUser < ActiveRecord::Migration[5.2]
   def up
     Migration::ColumnDropper.execute_drop(:posts, %i{group_locked_trust_level})