old_contents: // This is a manifest file that'll be compiled into application.js, which will include all the files
  // listed below.
  //
  // Any JavaScript/Coffee file within this directory, lib/assets/javascripts, vendor/assets/javascripts,
  // or vendor/assets/javascripts of plugins, if any, can be referenced here using a relative path.
  //
  // It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
  // compiled file.
  //
  // Read Sprockets README (https://github.com/sstephenson/sprockets#sprockets-directives) for details
  // about supported directives.
  
  // It is important that generated/vendor-bundle must be before bootstrap since it is exposing jQuery and jQuery-ujs
  //= require generated/vendor-bundle
  //= require generated/app-bundle
  
  // Must go after the vendor-bundle, b/c vendor-bundle has jQuery.
  //= require bootstrap-sprockets
  
  //= require turbolinks
  
  //= require react_on_rails
  
  // TODO: move to this separate file.
  $(document).on('ready page:load', function () {
    $('nav a').parents('li,ul').removeClass('active');
    $('nav a[href="' + this.location.pathname + '"]').parents('li,ul').addClass('active');
  });
  
new_contents: // This is a manifest file that'll be compiled into application.js, which will include all the files
  // listed below.
  //
  // Any JavaScript/Coffee file within this directory, lib/assets/javascripts, vendor/assets/javascripts,
  // or vendor/assets/javascripts of plugins, if any, can be referenced here using a relative path.
  //
  // It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
  // compiled file.
  //
  // Read Sprockets README (https://github.com/sstephenson/sprockets#sprockets-directives) for details
  // about supported directives.
  
  // CRITICAL that generated/vendor-bundle must be BEFORE bootstrap-sprockets and turbolinks since it is
  // exposing jQuery and jQuery-ujs
  //= require generated/vendor-bundle
  //= require generated/app-bundle
  
  // Next two depend on jQuery
  //= require turbolinks
  //= require bootstrap-sprockets
  
  //= require react_on_rails
  
  // TODO: move to this separate file.
  $(document).on('ready page:load', function () {
    $('nav a').parents('li,ul').removeClass('active');
    $('nav a[href="' + this.location.pathname + '"]').parents('li,ul').addClass('active');
  });
  
subject: Update application.js