Rebuild the image

docker build -t udpnginx .

Prep Nginx.conf for Environment Variable

cat nginx.conf | perl -pe 's/\$/\\\$/g' | perl -pe 's/\n/\\n/g' | perl -pe 's/ +/\ /g' > nginx.minified

Environment Variable used for nginx.conf

NGINX_CONF="Your nginx.conf Minified"