code: function poweredBy(app, config) {
      
      config = extend({}, defaults, config);
  
      if(config.disablePoweredBy) {
          return app.disable('x-powered-by');
      }
  
      if(config.poweredBy === false) {
          return;
      }
  
      app.use(function xPoweredBy(req, res, next) {
          res.header('x-powered-by', config.poweredBy);
          next();
      });
  }
docs: The configuration object will be the module's
  configuration object.
  We probably want to create an entry for this
  specific middleware...
  
  @param {Express} app Express application
  @param {Object} config Configuration object