Initializator.cs

using Microsoft.AspNet.Identity;
using Microsoft.AspNet.Identity.EntityFramework;
using SharedLibrary.Models;
using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Threading.Tasks;
using System.Web;

namespace SharedLibrary.Utils
{
    public class AppDatabaseInitializator
    {
        public static void Seed(ApplicationDbContext context)
        {

            InitializeRoles(context);
            InitializeUsers(context);
            InitializeBooks(context);
        }

        private static void InitializeUsers(ApplicationDbContext context)
        {
            var userStore = new UserStore<ApplicationUser>(context);
            var userManager = new ApplicationUserManager(userStore);

            var user1 = new ApplicationUser() { FirstName = "Mitre", LastName = "Mitrevski", Email = "mitre.mitrevski@gmail.com" };
            var user2 = new ApplicationUser() { FirstName = "Petre", LastName = "Petrevski", Email = "petre.petrevski@gmail.com" };
            var user3 = new ApplicationUser() { FirstName = "Stanko", LastName = "Stankovski", Email = "stanko.stankovski@gmail.com" };


            CreateUser(user1, userManager);
            CreateUser(user2, userManager);
            CreateUser(user3, userManager);

            context.SaveChanges();
        }

        private static void CreateUser(ApplicationUser user, UserManager<ApplicationUser> userManager)
        {

            var appUser = userManager.FindByEmail(user.Email);

            if (appUser == null)
            {
                //IdentityResult result = userManager.Create(user, "Test123@");
                var task = Task.Run(async () => await userManager.CreateAsync(user, "Test123@"));
                var result = task.Result;
                // referencing result should unwrap any errors.

                if (!result.Succeeded)
                    throw new Exception(result.Errors.ToString());
            }
        }

        private static void InitializeBooks(ApplicationDbContext context)
        {
            List<Book> books = new List<Book>() {
                new Book() { Id = 1, Name = "The Alchemist", Authors = "Paulo Coelho" },
                new Book() { Id = 2, Name = "The Very Hungry Caterpillar", Authors = "Eric Carie" },
                new Book() { Id = 3, Name = "Goodnight Moon", Authors = "Margaret Wise Brown" },
                new Book() { Name = "The Outsider: A Novel", Authors = "Stephen King" },
                new Book() { Name = "Just Mercy: A Story of Justice and Redemption", Authors = "Bryan Stevenson" }
            };

            context.Books.AddRange(books);
            context.SaveChanges();
        }

        private static void InitializeRoles(ApplicationDbContext context)
        {
            var roles = context.Roles.ToList();

            var adminRole = new IdentityRole("Administrator");
            var editorRole = new IdentityRole("Editor");
            var standardUserRole = new IdentityRole("StandardUser");

            if (roles == null || roles.Count == 0)
            {

                context.Roles.Add(adminRole);
                context.Roles.Add(editorRole);
                context.Roles.Add(standardUserRole);

            } else {

                if (!roles.Any(role => role.Name == "Administrator")) context.Roles.Add(adminRole);
                if (!roles.Any(role => role.Name == "Editor")) context.Roles.Add(editorRole);
                if (!roles.Any(role => role.Name == "StandardUser")) context.Roles.Add(standardUserRole);

            }

            context.SaveChanges();
        }
    }
}