npm WARN package.json [email protected] No repository field.

(bit trivial, but had me briefly confused)

- skip heroku login and .env copy steps, as my build takes care of that
- skip ssh key bits, as i use ssh -A from my laptop

index.html changes:
- add my own button code (instead of class one)
- use my own google analytics tags (though i seem to have forgot one of them)

web.js change:
- add some code used during exploration of this module, and javascript.  shows
  me how objects/variables work, demonstrated my suspicion that .env wasn't
  automagically passed to heroku (i missed the config:push bit in the
  instructions), played a bit with JSON parsing, and a simple
  dev-vs-production trigger