public class AppHost : AppHostBase
{
    //Tell ServiceStack the name of your app and which assemblies to scan for services
    public AppHost() : base("Hello ServiceStack!", 
       typeof(ServicesFromDll1).Assembly,
       typeof(ServicesFromDll2).Assembly
       /*, etc */) {}

    public override void Configure(Container container) {}
}

public class AppHost : AppHostBase
{
    public AppHost(): base("Hello ServiceStack!", typeof(ServicesFromDll1).Assembly) {}
    public override void Configure(Container container) {}

    //Provide Alternative way to inject IOC Container + Service Resolver strategy
    protected override ServiceManager CreateServiceManager(
        params Assembly[] assembliesWithServices)
    {       
        return new ServiceManager(new Container(),
            new ServiceController(() => assembliesWithServices.ToList()
                .SelectMany(x => x.GetTypes())));
    }
}

public class BasicAuthFeature : IPlugin 
{
    public string HtmlRedirect { get; set; }   //User-defined configuration

    public void Register(IAppHost appHost)
    {
        //Register Services exposed by this module
        appHost.RegisterService<AuthService>("/auth", "/auth/{provider}");
        appHost.RegisterService<AssignRolesService>("/assignroles");
        appHost.RegisterService<UnAssignRolesService>("/unassignroles");

        //Load dependent plugins
        appHost.LoadPlugin(new SessionFeature());
    }
}

Plugins.Add(new BasicAuthFeature { HtmlRedirect = "~/login" });