I am trying to implement Umbraco headrest project from Matt Brailsford. I have cloned the project from github and followed the instructions for setting it up for the Umbraco v8. I setup default umbraco starter kit and tried the basic setup for headrest with mapping from Home node to HomePageViewmodel as in

https://github.com/mattbrailsford/umbraco-headrest/tree/wip/v8

I am getting an error : InvalidOperationException: Don't know how to map Umbraco.Web.PublishedModels.Home to test.headrestv8.HomePageViewModel.

Here is the code for Configuration component is:

public class HeadRestConfigComponent : IComponent
{
    private readonly HeadRest _headRest;

    public HeadRestConfigComponent(HeadRest headRest)
        => _headRest = headRest;

    public void Initialize()
    {
        _headRest.ConfigureEndpoint(new HeadRestOptions
        {
            ViewModelMappings = new HeadRestViewModelMap()
        .For(Home.ModelTypeAlias).MapTo<HomePageViewModel>()
        });
        }

    public void Terminate() { }
}

public class HeadRestConfigComposer : ComponentComposer<HeadRestConfigComponent>
{ }

Right now i am only trying to map one field. The code for MapDefinition is:

public class TestHeadRestMapDefinition : IMapDefinition
{
    public void DefineMaps(UmbracoMapper mapper)
    {
        mapper.Define<Home, HomePageViewModel>(
            (source, context) => new HomePageViewModel(),      // Constructor function
            Map);            
    }
    private void Map(Home source, HomePageViewModel target, MapperContext context)
    {
        target.ColorTheme = source.ColorTheme;
    }
}

public class TestHeadRestMapDefinisionComposer : IUserComposer
{
    public void Compose(Composition composition)
    {
        composition.WithCollectionBuilder<MapDefinitionCollectionBuilder>()
            .Add<TestHeadRestMapDefinition>();
    }
}

The code ViewModel is:

public class HomePageViewModel
{
    public string ColorTheme { get; set; }

}

I can't figure out whats going wrong or did i set it up in a wrong way? Any help would be really appreciated.