Add Docker support

[noonien]

No description provided.

[asmundg]

Saved me three lines of typing, thanks!. :)

[schickling]

@jehiah any plans to publish an official image on Dockerhub like for NSQ?

[raphink]

An official image would be very useful. There's tons of them on Dockerhub, mostly pretty bad or old.

[kop]

I'd like to join to the request for official Docker image. There are really a lot of images exists, but they all come with latest tag only. Having correct version tags would be very helpful.

[bfirsh]

Would be great to be able to do docker run bitly/oauth2_proxy at least. ✨ 🐳 ✨

[zoidyzoidzoid]

It looks like the docker image in the Docker support issue is missing now too, and like other people have mentioned all Docker images I've seen in Google results are outdated.

Would there be interest in having an officially supported one, or at least mentioning one in the README for the repo?

I'm working on one that looks something like:

FROM alpine:3.4

RUN apk add --no-cache --virtual .fetch-deps \
    ca-certificates \
    openssl \
    tar \
  && wget -O /oauth2_proxy.tar.gz https://github.com/bitly/oauth2_proxy/releases/download/v2.1/oauth2_proxy-2.1.linux-amd64.go1.6.tar.gz \
  && tar -fxz /oauth2_proxy.tar.gz \
  && rm /oauth2_proxy.tar.gz \
  && apk del .fetch-deps

ENTRYPOINT ["/oauth2_proxy"]

This is an awesome amazing project, and it'd be awesome to have an official image.

[pataquets]

Cross-linking to more recent #460