diff --git a/db/migrate/20190723152256_delete_contents_is_null_for_challenge_answers.rb b/db/migrate/20190723152256_delete_contents_is_null_for_challenge_answers.rb
new file mode 100644
index 000000000..a85152894
--- /dev/null
+++ b/db/migrate/20190723152256_delete_contents_is_null_for_challenge_answers.rb
@@ -0,0 +1,6 @@
+class DeleteContentsIsNullForChallengeAnswers < ActiveRecord::Migration[5.2]
+  def change
+    contents = ChallengeAnswer.where("contents = ''")
+    contents.delete_all
+  end
+end