As any rubyist know,
ENV lets you read variables from your local environment. This works pretty well for web projects, but you can't rely on this for a RubyMotion project, since the final product will be placed in a device without access to this data.
An easy solution could be storing your ENV vars inside the app's configuration plist on build time:
app.info_plist['ID'] = ENV['ID'] app.info_plist['SECRET'] = ENV['SECRET']
... and accessing them in your code through the mainBundle:
id = NSBundle.mainBundle.objectForInfoDictionaryKey('ID')