diff --git a/db/migrate/20190725024516_modify_attachment_url_for_challenge_answer.rb b/db/migrate/20190725024516_modify_attachment_url_for_challenge_answer.rb
deleted file mode 100644
index 41840bac1..000000000
--- a/db/migrate/20190725024516_modify_attachment_url_for_challenge_answer.rb
+++ /dev/null
@@ -1,7 +0,0 @@
-class ModifyAttachmentUrlForChallengeAnswer < ActiveRecord::Migration[5.2]
-  def change
-    ChallengeChoose.find_each do |cc|
-      cc.update_column(:subject, cc.subject.gsub("(/attachments/download", "(/api/attachments")) if cc.subject.present?
-    end
-  end
-end