I wanted to check for other options, but based on the `Brocfile.js` from the blueprint [here](https://github.com/stefanpenner/ember-cli/blob/master/blueprint/Brocfile.js#L11):
```
var env = require('broccoli-env').getEnv();
```
which means that it is getting it from the `process.env` value based on the code [here](https://github.com/joliss/broccoli-env/blob/master/index.js#L3):
```
var env = process.env.BROCCOLI_ENV || 'development'
```
So I guess that change need to reflect the blueprint as well?