How to add reference to System.Web.Optimization for MVC-3-converted-to-4 app

Update
Version 1.1.x is available, read the release notes: https://www.nuget.org/packages/Microsoft.AspNet.Web.Optimization

---

The Microsoft.Web.Optimization package is now obsolete. With ASP.NET (MVC) 4 and higher you should install the Microsoft ASP.NET Web Optimization Framework:

• Install the package from nuget:

  Install-Package Microsoft.AspNet.Web.Optimization
  

• Create and configure bundle(s) in App_Start\BundleConfig.cs:

  public class BundleConfig
  {
      public static void RegisterBundles(BundleCollection bundles) {
          bundles.Add(new ScriptBundle("~/Scripts/jquery").Include(
              "~/Scripts/Lib/jquery/jquery-{version}.js",
              "~/Scripts/Lib/jquery/jquery.*",
              "~/Scripts/Lib/jquery/jquery-ui-{version}.js")
          );
  
          bundles.Add(new ScriptBundle("~/Scripts/knockout").Include(
               "~/Scripts/Lib/knockout/knockout-{version}.js",
               "~/Scripts/Lib/knockout/knockout-deferred-updates.js")
          );
      }
  }
  

• Call the RegisterBundles() function from Application_Start() in your global.asax.cs:

  using System.Web.Optimization;
  
  protected void Application_Start() {
       ...
       BundleConfig.RegisterBundles(BundleTable.Bundles);
       ...
  }
  

• In your view.cshtml include the Optimization namespace and render the bundle(s):

  @using System.Web.Optimization
  
  @Scripts.Render("~/Scripts/jquery")
  @Scripts.Render("~/Scripts/knockout")
  

See http://www.asp.net/mvc/overview/performance/bundling-and-minification for more information