Settings.define 'setting', :environment => 'ENV_VAR'

[orlin]

The title does not work. The following does:
Settings.environment_variables 'ENV_VAR' => 'setting'

Also, the README says Settings.use_environment (no such method) - which changed to environment_variables?

[mrflip]

Changed interface and reconciled documentation n light of this and other issues.

You should now use

Settings.env_vars :setting => 'ENV_VAR'

or

Settings.define :setting, :env_var => 'ENV_VAR'

See examples/env_var_script.rb for a demonstration

Notice that these simple keys must be symbols, not strings.