Support SSL redirect

If enforce_ssl attribute is true, then the nginx proxy will redirect
HTTP to HTTPS. By default there are no SSL configuration options set
with this as we're using AWS ELB to terminate HTTPS. Adding the ssl
certificate and key, plus additional options was added to lay the
groundwork for potential expansion on this, but it needs to be tested
(which includes building a self-signed certificate for the repository
to do the testing).

Background on this configuration method:

http://frankmitchell.org/2013/05/https-elb/
Merge pull request #14 from opscode-cookbooks/elb-ssl-support

Support SSL redirect
Version bump to 2.1.0
Publish 2.1.0 Changelog
Version bump to 2.1.1 (for development)
use correct attribute forcing ssl in the template
Version bump to 2.1.2
Publish 2.1.2 Changelog
Version bump to 2.1.3 (for development)
Change .env to .env.production

In service to https://github.com/opscode/supermarket/pull/399 this changes
the .env template to be .env.production as we're now taking advantage of
dotenvs environment features. .env.production will take precedence over
.env.
Merge pull request #16 from opscode-cookbooks/dot-env-prod

Change .env to .env.production
Allow protocol to be configured

A protocol can be defined to generate absolute URLs within Supermarket
so this provides an attribute that can be changed depending on the
environments needs.