Use Zeit's Now as free hosting that supports Docker

[agilgur5]

https://zeit.co/now is free for OSS projects (related to #68 #43 )

[agilgur5]

Per #43 (comment), it's running now via Docker on Heroku once again, so this is no longer necessary. Though since the Heroku version is currently running under my account, it's using my free dyno hours instead of VRRG's. Zeit Now is free for OSS projects in general (no limit on usage) so at some point would be better to use that and update all the relevant links (including the repo link, which I don't have permission to change)

[agilgur5]

Heroku free tier is going away per https://blog.heroku.com/next-chapter, so maybe want to get this working at least for reference