add completed submitters verification method

db/migrate/20250901110606_add_verification_method_to_completed_submitters.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AddVerificationMethodToCompletedSubmitters < ActiveRecord::Migration[8.0]
+  def change
+    add_column :completed_submitters, :verification_method, :string
+  end
+end