Startup.cs

using GitHubAppDotnetSample.Filters;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;

namespace GitHubAppDotnetSample
{
    public class Startup
    {
        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
        public void ConfigureServices(IServiceCollection services)
        {

            services.AddTransient<CreateGitHubClientFilter>();

            services
                .AddMvcCore(options =>
                {
                    options.Filters.AddService<CreateGitHubClientFilter>();
                }).AddGitHubWebHooks();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            app.UseMvc();
        }
    }
}