add expire at

db/migrate/20240801125558_add_expire_at_to_submissions.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AddExpireAtToSubmissions < ActiveRecord::Migration[7.1]
+  def change
+    add_column :submissions, :expire_at, :datetime
+  end
+end