Custom hapi server example handle static files (#6822)

While implementing hapi as a custom server, I found a minor issue. The example provided isn't showing that we also need to serve static files using next. This change should fix that. Thanks!

examples/custom-server-hapi/server.js

@@ -32,6 +32,12 @@ app.prepare().then(async () => {
     handler: nextHandlerWrapper(app)
   })
 
+  server.route({
+    method: 'GET',
+    path: '/static/{p*}' /* use next to handle static files */,
+    handler: nextHandlerWrapper(app)
+  })
+
   server.route({
     method: 'GET',
     path: '/{p*}' /* catch all route */,