Program.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;

namespace WaitTime
{
    public class Program
    {
        public static void Main(string[] args)
        {
            CreateWebHostBuilder(args).Build().Run();
        }

        public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .ConfigureAppConfiguration((context, builder) => builder
                    .AddJsonFile("appsettings.json")
                    .AddJsonFile($"appsettings.{context.HostingEnvironment.EnvironmentName}.json")
                    .AddEnvironmentVariables()
                    .Build())
                .UseStartup<Startup>();
    }
}