Production ini

I'm setting up a staging server for us again and it's time I pushed this.

It adds a production.ini and slims down development.ini.

 - development.ini is just the minimum necessary for development
 - production.ini has all more of the options shown with examples and detailed comments

Beyond valuable documentation, this means we get a sane default deployment with production settings in heroku or dokku environments since the Procfile to uses production.ini by default. 

Now elasticsearch and the mail relay can be configured from the environment. I've installed a plugin for this in our dokku. That means deploying a new app needs two new commands (only the first time):

``` bash
$ git push dokku@dokku.hypothes.is:feature feature:master
$ ssh dokku@dokku.hypothes.is docker-options:add "--link elasticsearch:elasticsearch"
$ ssh dokku@dokku.hypothes.is docker-options:add "--link postfix:mail"
```

Unfortunately, emails from dokku will go to your spam box until we do some sender rewriting.

I would like this because we can keep private branches that have our production.ini (currently in puppet) and manage deploys with dokku instead.

This will make it easier to manage stage and prod configurations.