docs: function getEnvironment(opts) {
    if (opts.app) {
      // Merge app env over the process env and return.
      var processEnv = _.cloneDeep(process.env);
      var appEnv = opts.app.env.getEnv();
      return _.merge(processEnv, appEnv);
    } else {
      // Just use process env.
      return process.env;
    }
  }