Add dockerfile and Glide files

[calavera]

Hi!

I added a couple of changes to the project:

1. A brand new Dockerfile, so people can use go-torch from within
   a docker container using docker run uber/go-torch go-torch ...
2. I removed the old Godeps file and added Glide files as requested.

[sandlerben]

I've been using Godep for vendoring and it's been working quite well. Do you like bmizerany/vendor better?

[calavera]

It's much more simple to use since it leaves all the dependency loading to Go's new vendoring

[sandlerben]

Cool!

[prashantv]

Thanks for the change @calavera. The docker file seems great.

A couple of things:

1. Can you please fill out the Uber Contributor License Agreement
2. Rather than vendor, we prefer to use glide, and only check in the glide.yaml and glide.lock.

[calavera]

@prashantv I've signed the CLA already and added the Glide files.

[prashantv]

do you think it's worth using the alpine image to make this smaller?

[calavera]

done, I had to install git and change the tar command, but the resulting image should still be smaller.

[prashantv]

lgtm, just a couple of small questions

[prashantv]

Thanks @calavera!