Fix broken Dockerfile to use official node image instead

[andyshinn]

As I was working on #538, I ran the server in Docker. But the default Dockerfile was broken. I updated to use the official Node image with ONBUILD hooks instead. Also added some information about it in the docs (the two commands I were using together to build and run).

I did try Node 4.0.0, but it looks like some other dependencies are still broken on 4.0.0 (namely socketio/socket.io#2228).

[espadrine]

There seems to be a lot of spaces at the end of this line

[andyshinn]

Oops, I'll re-enable my whitespace line trimmer!

[espadrine]

Thanks for contributing!

Could you detail how libcairo gets installed? Do the badges get the correct width computation?

[andyshinn]

libcairo2 gets installed in the node upstream image, buildpack-deps:jessie (based on Debian Jessie). The specific versions are:

ii  libcairo-gobject2:amd64              1.14.0-2.1              amd64                   Cairo 2D vector graphics library (GObject library)
ii  libcairo-script-interpreter2:amd64   1.14.0-2.1              amd64                   Cairo 2D vector graphics library (script interpreter)
ii  libcairo2:amd64                      1.14.0-2.1              amd64                   Cairo 2D vector graphics library
ii  libcairo2-dev                        1.14.0-2.1              amd64                   Development files for the Cairo 2D graphics library

If widths were off by a pixel or two then I didn't notice, is there an easy way for me to check?

[espadrine]

Thanks!