code: function build(app) {
    console.log('Building Zealder bundles...');
  
    let promises = [];
  
    // make server bundles
    if ('production' === app.get('env')) {
      bundleServer(app, promises);
    }
  
    // make bundle for all sites
    bundleSites(app, promises);
  
    Promise.all(promises).then(function() {
      app.debug('build completed!');
      // all done
      return process.exit();
    });
  }
docs: builds app