Adds docker configuration files to develop locally using containers.

[josecanhelp]

• Adds develop script to initiate containers and to easily pass knex and npm commands through to containers.
• Includes Dockerfile to generate node image.
• Includes docker-compose file to define containerized environment.

[alarner]

@josecanhelp this is awesome! I haven't tested it out yet, but one thing I noticed was that you have a new docker/local.js file. Would it be possible to use the existing environment based configuration system instead and move that file to config/env/docker.js (here's an example of how it's done for heroku: https://github.com/alarner/perk/blob/master/config/env/heroku.js). This way we can keep all of the configuration in the config director and should just be able to set NODE_ENV=docker when running inside of the container. I'm super excited to actually try it out!

Since I'm a docker newbie would you mind sending me the commands I need to get started? I assume it something like docker-compose run but not entirely sure.

[josecanhelp]

@alarner I forgot to include in the PR that I also submitted a separate PR for the Perk Docs.

I used a helper script that was created by Chris Fidao @fideloper and modified it to work for us here. Essentially, the script facilitates the docker-compose commands and makes it a bit simpler to use. You can view the source of the develop file to get a clear understanding of what is happening.

I will take a look at how you implemented the heroku configuration file and try to replicate that for docker. I might have to hit you up for some clarification.