Add one (functional) line to this project - good first contribution

[MikeRalphson]

See https://github.com/jkup/one-line/blob/master/CONTRIBUTING.md

Multiple Pull-Requests are welcome.

[samuelteixeiras]

Days left to new year :)
Math.round(( new Date().setFullYear(new Date().getFullYear() + 1, 0, 1) - new Date() )/(1000 * 60 * 60 * 24))

[scorpionhiccup]

@MikeRalphson have a look at the PR i created, when you get the time.