RegisterMethods.cs

        [HttpGet]
        public IActionResult Register()
        {
            return View();
        }

        [HttpPost]
        public async Task<IActionResult> Register(UserRegisterModel model)
        {
            var exists = _db.Users.SingleOrDefault(u => u.Email.Equals(model.Username));
            if (exists != null)
                return View();

            var result = await _userManager.CreateAsync(new IdentityUser(model.Username), model.Password);

            if (result.Succeeded)
                return RedirectToAction("Index", "Home");

            return View();
        }