Add audit log to registrant verifications

Closes #1425

test/models/registrant_verification_test.rb

@@ -0,0 +1,12 @@
+require 'test_helper'
+
+class RegistrantVerificationTest < ActiveSupport::TestCase
+  def test_audit_log
+    registrant_verification = registrant_verifications(:one)
+    random_action = "random#{rand(100)}"
+
+    assert_difference -> { PaperTrail::Version.count } do
+      registrant_verification.update_attributes!(action: random_action)
+    end
+  end
+end