Program.cs

using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using System;
using Group_Guide.Data;
using Azure.Identity;
using System.Threading.Tasks;
using Microsoft.Extensions.DependencyInjection;

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

            using var scope = host.Services.CreateScope();
            var dbSeeder = (DatabaseSeeder)scope.ServiceProvider.GetService(typeof(DatabaseSeeder));
            await dbSeeder.SeedAsync();

            await host.RunAsync();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args).ConfigureAppConfiguration((context, config) =>
                {
                    var keyVaultEndpoint = new Uri(Environment.GetEnvironmentVariable("VaultUri"));
                    config.AddAzureKeyVault(keyVaultEndpoint, new DefaultAzureCredential());
                }).ConfigureWebHostDefaults(webBuilder =>
                    {
                        webBuilder.UseStartup<Startup>();
                    });
    }
}