Add default functions file for convenience

Author: BenSurgisonGDS

prototype-starter/app/functions.js

@@ -0,0 +1,9 @@
+//
+// For guidance on how to create functions see:
+// https://prototype-kit.service.gov.uk/docs/functions
+//
+
+const govukPrototypeKit = require('govuk-prototype-kit')
+const addFunction = govukPrototypeKit.views.addFunction
+
+// Add your functions here