Startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Localization;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using System.Collections.Generic;
using System.Globalization;
using WebApplicationRestaurant.Data;
using WebApplicationRestaurant.Models;

namespace WebApplicationRestaurant
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        public void ConfigureServices(IServiceCollection services)
        {
            services.AddDbContext<ApplicationContext>(options => 
            {
                options.UseSqlServer(Configuration.GetConnectionString("SqlServerDevelopmentConnection"));
                options.LogTo(message => System.Diagnostics.Debug.WriteLine(message));
            });

            services.AddIdentity<User, IdentityRole>(options =>
            {
                options.Password.RequiredLength = 5;   // ìèíèìàëüíàÿ äëèíà
                options.Password.RequireNonAlphanumeric = false;   // òðåáóþòñÿ ëè íå àëôàâèòíî-öèôðîâûå ñèìâîëû
                options.Password.RequireLowercase = false; // òðåáóþòñÿ ëè ñèìâîëû â íèæíåì ðåãèñòðå
                options.Password.RequireUppercase = false; // òðåáóþòñÿ ëè ñèìâîëû â âåðõíåì ðåãèñòðå
                options.Password.RequireDigit = false; // òðåáóþòñÿ ëè öèôðû
            }).AddEntityFrameworkStores<ApplicationContext>();

            services.AddMvc();

            services.AddDistributedMemoryCache();
            services.AddSession();
        }

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
                app.UseHsts();
            }
            app.UseHttpsRedirection();
            app.UseStaticFiles();

            app.UseRequestLocalization();

            var customCulture = new CultureInfo("ru-RU");
            customCulture.NumberFormat.NumberDecimalSeparator = ".";

            CultureInfo.DefaultThreadCurrentCulture = customCulture;
            CultureInfo.DefaultThreadCurrentUICulture = customCulture;

            app.UseRouting();

            app.UseAuthentication();
            app.UseAuthorization();

            app.UseSession();

            app.UseEndpoints(endpoints =>
            {
                app.UseEndpoints(endpoints =>
                {
                    endpoints.MapControllerRoute(
                      name: "areas",
                      pattern: "{area:exists}/{controller=Home}/{action=Index}/{id?}"
                    );
                });

                endpoints.MapControllerRoute(
                    name: "default",
                    pattern: "{controller=Home}/{action=Index}/{id?}");
            });
        }
    }
}