aspnetcore/samples/WelcomePageSample/Startup.cs

using Microsoft.AspNet.Builder;
using Microsoft.AspNet.Hosting;

namespace WelcomePageSample
{
    public class Startup
    {
        public void Configure(IApplicationBuilder app)
        {
            app.UseWelcomePage();
        }

        public static void Main(string[] args)
        {
            var application = new WebApplicationBuilder()
                .UseConfiguration(WebApplicationConfiguration.GetDefault(args))
                .UseStartup<Startup>()
                .Build();

            application.Run();
        }
    }
}