slow deployment on heroku

Our deploys on heroku are taking quite a long time (30+ seconds) which incurs quite a bit of downtime during deployment. A second or two is acceptable, but 30 seconds is not. Any idea on how I can improve the speed of `npm start`? Locally it runs significantly faster...

From logs:

```
2016-05-18T17:39:01.756601+00:00 heroku[web.1]: Starting process with command `npm start`
2016-05-18T17:39:05.413614+00:00 app[web.1]:
2016-05-18T17:39:05.413630+00:00 app[web.1]: > react-redux-universal-hot-example@0.9.0 start /app
2016-05-18T17:39:05.413631+00:00 app[web.1]: > concurrent --kill-others "npm run start-prod"
2016-05-18T17:39:05.413632+00:00 app[web.1]:
2016-05-18T17:39:07.267232+00:00 app[web.1]: [0]
2016-05-18T17:39:07.267242+00:00 app[web.1]: [0] > react-redux-universal-hot-example@0.9.0 start-prod /app
2016-05-18T17:39:07.267243+00:00 app[web.1]: [0] > better-npm-run start-prod
2016-05-18T17:39:07.267243+00:00 app[web.1]: [0]
2016-05-18T17:39:07.465188+00:00 app[web.1]: [0] Executing script: start-prod
2016-05-18T17:39:07.431925+00:00 app[web.1]: [0] running better-npm-run in /app
2016-05-18T17:39:07.465198+00:00 app[web.1]: [0]
2016-05-18T17:39:07.465198+00:00 app[web.1]: [0] to be executed: node ./bin/server.js
2016-05-18T17:39:38.524212+00:00 app[web.1]: [0] ----
2016-05-18T17:39:38.524224+00:00 app[web.1]: [0] ==> ✅ React Redux Example is running, talking to API server on 3000.
2016-05-18T17:39:38.524843+00:00 app[web.1]: [0] ==> 💻 Open http://localhost:20037 in a browser to view the app.1
```