OAuth2 Proxy Docker image

https://github.com/bitly/oauth2_proxy

GitHub example (testing only, you should enable TLS in production):

docker run --rm -p 4180:4180 \
    -e OAUTH2_PROXY_CLIENT_ID=GITHUB_CLIENT_ID \
    -e OAUTH2_PROXY_CLIENT_SECRET=GITHUB_SECRET \
    oauth2-proxy \
    --provider=github \
    --github-org=openmicroscopy \
    --github-team=devops \
    --email-domain=* \
    --cookie-secure=false \
    --upstream=file:///