startup.cs

public void ConfigureServices(IServiceCollection services)
{
    services.AddCors();
    services.AddMvc(options =>
    {
        var templates = new Dictionary<Type, object>
        {
            { typeof(GameResponse), new GameSirenResponse() }
        };

        options.OutputFormatters.Add(new SirenOutputFormatter(templates));
    });

    services.AddSwaggerGen(c =>
    {
        c.SwaggerDoc("v1", new Info { Title = "Hangman Api v1.0", Version = "v1" });
        c.IncludeXmlComments("wwwroot/Hangman.Api.xml");
    });
}