Add updating testing.

## Validation
Please test this by deleting `node_modules` and then following the instructions in the updated README.md. It should work without any finagling on your part besides setting your project port number inside `project_user_specific.yml` as described in the readme.

I would like @tglines to review this and if anyone else has time, please take a look and see if it works out of the box.

cc: @UseAllFive/useallfive-developers