Program.cs

using System;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using OOL_API.Data;

namespace OOL_API
{
    public class Program
    {
        public static async Task Main(string[] args)
        {
            var host = CreateHostBuilder(args).Build();

            await CreateDbIfNotExists(host);

            await host.RunAsync();
        }

        private static async Task CreateDbIfNotExists(IHost host)
        {
            using var scope = host.Services.CreateScope();

            var services = scope.ServiceProvider;

            try
            {
                var context = services.GetRequiredService<StudioContext>();

                var initializer = services.GetRequiredService<DbInitializer>();

                await initializer.Initialize(context);
            }
            catch (Exception ex)
            {
                var logger = services.GetRequiredService<ILogger<Program>>();
                logger.LogError(ex, message: "An error occurred creating the DB.");
            }
        }

#if DEBUG

        public static IHostBuilder CreateHostBuilder(string[] args)
        {
            return Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>()
                        .UseUrls("http://*:5000");
                });
        }
#else
        public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
           .ConfigureWebHostDefaults(webBuilder =>
           {
               var port = Environment.GetEnvironmentVariable("PORT") ?? "443";

               webBuilder.UseStartup<Startup>()
               .UseUrls("https://*:" + port);
           });
#endif
    }
}