Fix Idempotency of Database Handling

1. 'reset_db' was doing too much on its own. Delegated to Rails' built
   in Rake tasks
2. Non-reset case updated to attempt to create DB (always safe), and to
   update test DB if need be

Resolves #15
Merge pull request #16 from jherdman/15-idempotent-database-script

Fix Idempotency of Database Handling
Make SSL optional and off by default

Off by default makes sense since rails-last-mile is primarily intended
for development.
Add ability to customize unicorn

Now uses unicorn-chef's configuration generation
Whitespace and add support for proxy_set_header X-Forwarded-Proto $scheme to support force_ssl for Rails. Otherwise, nginx tries to proxy http, and things go all wonky.
Merge pull request #17 from axelson/ssl_optional

Using SSL on NGINX by default causes issues
Merge pull request #18 from axelson/unicorn_config

Unicorn config
Merge pull request #19 from PrecisionNutrition/add-x-forwarded-proto-support

Support X-Forwarded-Proto header in nginx config