Executing `ember build` fails in either of two ways:
Using `ember build`:
```
Step 19 : RUN ember build
---> Running in e9b7ab3db5a0
DEPRECATION: Node v0.10.36 is no longer supported by Ember CLI. Please update to a more recent version of Node
undefined
version: 1.13.12
Could not find watchman, falling back to NodeWatcher for file system events.
Visit http://www.ember-cli.com/user-guide/#watchman for more info.
BuildingRule "disallowVar" is already registered
AssertionError: Rule "disallowVar" is already registered
at NodeConfiguration.Configuration.registerRule (/var/www/roundcube-shell.git/node_modules/ember-suave/node_modules/broccoli-jscs/node_modules/jscs/lib/config/configuration.js:864:5)
at NodeConfiguration.Configuration._loadAdditionalRule (/var/www/roundcube-shell.git/node_modules/ember-suave/node_modules/broccoli-jscs/node_modules/jscs/lib/config/configuration.js:825:10)
at NodeConfiguration.<anonymous> (/var/www/roundcube-shell.git/node_modules/ember-suave/node_modules/broccoli-jscs/node_modules/jscs/lib/config/node-configuration.js:213:61)
at Array.forEach (native)
at NodeConfiguration._loadAdditionalRule (/var/www/roundcube-shell.git/node_modules/ember-suave/node_modules/broccoli-jscs/node_modules/jscs/lib/config/node-configuration.js:211:61)
at NodeConfiguration.<anonymous> (/var/www/roundcube-shell.git/node_modules/ember-suave/node_modules/broccoli-jscs/node_modules/jscs/lib/config/configuration.js:502:18)
at Array.forEach (native)
at NodeConfiguration.Configuration._processConfig (/var/www/roundcube-shell.git/node_modules/ember-suave/node_modules/broccoli-jscs/node_modules/jscs/lib/config/configuration.js:501:33)
at NodeConfiguration.Configuration._loadPreset (/var/www/roundcube-shell.git/node_modules/ember-suave/node_modules/broccoli-jscs/node_modules/jscs/lib/config/configuration.js:748:10)
at NodeConfiguration._loadPreset (/var/www/roundcube-shell.git/node_modules/ember-suave/node_modules/broccoli-jscs/node_modules/jscs/lib/config/node-configuration.js:163:41)
The command '/bin/sh -c ember build' returned a non-zero code: 1
```
Using `ember build --environment production`:
```
Step 19 : RUN ember build --environment production
---> Running in d651f8b352c0
DEPRECATION: Node v0.10.36 is no longer supported by Ember CLI. Please update to a more recent version of Node
undefined
version: 1.13.12
Could not find watchman, falling back to NodeWatcher for file system events.
Visit http://www.ember-cli.com/user-guide/#watchman for more info.
BuildingBuilding.Building..Building...BuildingBuilding.Building..Building...BuildingBuilding.Building..Build failed.
File: assets/roundcube-shell.css
Promise is not defined
ReferenceError: Promise is not defined
at LazyResult.async (/var/www/roundcube-shell.git/node_modules/ember-cli-autoprefixer/node_modules/broccoli-autoprefixer/node_modules/postcss/lib/lazy-result.js:152:31)
at LazyResult.then (/var/www/roundcube-shell.git/node_modules/ember-cli-autoprefixer/node_modules/broccoli-autoprefixer/node_modules/postcss/lib/lazy-result.js:75:21)
at AutoprefixerFilter.processString (/var/www/roundcube-shell.git/node_modules/ember-cli-autoprefixer/node_modules/broccoli-autoprefixer/index.js:38:4)
at Object.module.exports.processString (/var/www/roundcube-shell.git/node_modules/ember-cli-autoprefixer/node_modules/broccoli-autoprefixer/node_modules/broccoli-persistent-filter/lib/strategies/default.js:7:16)
at Processor.processString (/var/www/roundcube-shell.git/node_modules/ember-cli-autoprefixer/node_modules/broccoli-autoprefixer/node_modules/broccoli-persistent-filter/lib/processor.js:20:25)
at /var/www/roundcube-shell.git/node_modules/ember-cli-autoprefixer/node_modules/broccoli-autoprefixer/node_modules/broccoli-persistent-filter/index.js:185:16
at lib$rsvp$$internal$$initializePromise (/var/www/roundcube-shell.git/node_modules/ember-cli-autoprefixer/node_modules/broccoli-autoprefixer/node_modules/broccoli-persistent-filter/node_modules/rsvp/dist/rsvp.js:541:9)
at new lib$rsvp$promise$$Promise (/var/www/roundcube-shell.git/node_modules/ember-cli-autoprefixer/node_modules/broccoli-autoprefixer/node_modules/broccoli-persistent-filter/node_modules/rsvp/dist/rsvp.js:757:9)
at invoke (/var/www/roundcube-shell.git/node_modules/ember-cli-autoprefixer/node_modules/broccoli-autoprefixer/node_modules/broccoli-persistent-filter/index.js:184:10)
at AutoprefixerFilter.Filter.processFile (/var/www/roundcube-shell.git/node_modules/ember-cli-autoprefixer/node_modules/broccoli-autoprefixer/node_modules/broccoli-persistent-filter/index.js:201:16)
The command '/bin/sh -c ember build --environment production' returned a non-zero code: 1
```