Remove Nanobox deployment method instructions.

This method is broken and appears to have been broken for a while. After spending some time attempting to fix it, I'm removing it for now but would consider PRs from folks with more Nanobox experience.

README.md

@@ -21,7 +21,6 @@ work.
 - [Deployment](#deployment)
   - [AWS Elastic Beanstalk](#aws-elastic-beanstalk)
   - [Docker](#docker)
-  - [Nanobox](#nanobox)
   - [Heroku](#heroku)
   - [Manual](#manual)
 - [Configuration](#configuration)
@@ -109,33 +108,6 @@ The app should now be locally available at
 [Get Started, Part 6: Deploy your app](https://docs.docker.com/get-started/part6/)
 for detailed information about how to deployment methods with Docker.
 
-### Nanobox
-
-An example [Nanobox](https://nanobox.io/) configuration, `boxfile.yml`, is
-provided with Baby Buddy. The steps below are a rough guide to deployment. See
-[Create and Deploy a Custom Django App](https://guides.nanobox.io/python/django/)
-for detailed information about Nanobox's deployment and configuration process.
-
-1. Clone/download the Baby Buddy repo
-
-        git clone https://github.com/cdubz/babybuddy.git
-
-1. Enter the cloned/downloaded directory
-
-        cd babybuddy
-
-1. Add the `SECRET_KEY` and `DJANGO_SETTINGS_MODULE` environment variables
-
-        nanobox evar add DJANGO_SETTINGS_MODULE=babybuddy.settings.nanobox
-        nanobox evar add SECRET_KEY=<CHANGE TO SOMETHING RANDOM>
-
-    *See [Configuration](#configuration) for other settings that can be
-    controlled by environment variables.*
-
-1. Deploy! :rocket:
-
-        nanobox deploy
-
 ### Heroku
 
 [![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy)

boxfile.yml

@@ -1,34 +0,0 @@
-run.config:
-  engine: python
-
-  cache_dirs:
-    - node_modules
-
-  extra_packages:
-    - nodejs
-    - nginx
-
-  extra_path_dirs:
-    - node_modules/.bin
-
-  extra_steps:
-    - pip install pipenv gunicorn
-    - pipenv install --system --deploy
-    - npm install
-
-deploy.config:
-  extra_steps:
-    - gulp build
-    - python manage.py collectstatic --no-input --clear
-
-  before_live:
-    web.main:
-      - python manage.py migrate --fake-initial
-
-web.main:
-  start:
-    nginx: nginx -c /app/etc/nginx.conf
-    django: gunicorn -c /app/etc/gunicorn.py babybuddy.wsgi
-
-data.db:
-  image: nanobox/postgresql:9.5