Add an example usage project

[adipasquale]

Thanks for the super useful package! I had quite a hard time setting it up for various reasons so I wrote a rather detailed step by step tutorial on how to get the right keys and certificates: https://github.com/adipasquale/passe-passe

I also wrote a super small Node Express API that uses this lib and can be quickly deployed to Heroku.

Would you be interested in listing it as a useful resource on the pass-js README? I'd be happy to backport a few of the instructions updates directly into the project's README as well if you're open for PRs.

[JaapWeijland]

@adipasquale The existence of your guide made me consider using this package. The maintainer really should include it in its README.

[PatrickQuintal]

@adipasquale @JaapWeijland

Feel free to make a PR :P

[wong0]

Could you also add to this demo, to include the JS usage?

I am having some issues with constructing a new template according to the instructions provided.