Not able to see startup.auth.cs

I am using .NET MVC 5. I do not see startup.auth.cs. I am trying to do external Google Authenication and need to reference somethings.

What NuGet package do I need to get in order to get the startup.auth.cs to show up?

I got the following Nuget:

Microsoft.Owin.Security and Microsoft.Owin.Security.Google but did not see the file generated.