Dockerize

Adds a `Dockerfile` to containerize this environment.  Also, adds a bit more in the README on how to use it, as well as a `.gitignore` to clear away any cruft left behind from editing files in the `notebooks` folder.
Docker only runs natively on Linux.  To make it run on a Mac or Windows,
you have to run it using something called boot2docker, which is a minimal
Linux virtual machine with Docker installed that runs under VirtualBox.

Boot2docker sets up a private network for you, and gives you this address
to access the VM that is actually running your containers.  (You could also
set up a mapping in VirtualBox itself to do it.)

Andrew

ps -- I put together this intro to Docker, if you're interested:

http://odewahn.github.io/docker-jumpstart

It's a bit out of date, but it covers a lot of the general, day-to-day
stuff about it.

On Mon, Dec 29, 2014 at 7:38 AM, Cyrille Rossant <notifications@github.com>
wrote:

> In README.md
> <https://github.com/rossant/ipymd/pull/3#discussion-diff-22310423>:
>
> > @@ -72,3 +72,28 @@ To use the Atlas format, put this in your config file:
> >  ```python
> >  c.NotebookApp.contents_manager_class = 'ipymd.AtlasContentsManager'
> >  ```
> > +
> > +## Using Docker
> > +
> > +You can also run this using Docker on a Mac (via boot2docker) or Linux.  (NB: you need docker and boot2docker 1.3+.  Also, it's set up by default using the AtlasContentsManager.)
> > +
> > +Run this command within the directory containing the notebooks you want to edit.  (Note that docker will pull down the entire image the first time you run this command, so it may take a while.):
> > +
> > +```
> > +docker run -it -p 8888:8888 -v $(pwd):/usr/data odewahn/ipymd
> > +```
> > +
> > +Once the container starts, open your browser:
> > +
> > +* On a Mac, go to `192.168.59.103:8888`
>
> Just curious, why is there a different address on a Mac?
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/rossant/ipymd/pull/3/files#r22310423>.
>