Added SignMeIn

HomeController.cs

public async Task<IActionResult> SignMeIn()
{
  // Just do a real basic login.
  var claims = new List<Claim>
  { 
      new Claim(ClaimTypes.Name, "ajevans"),
      new Claim("FullName", "Alistair Evans"),
      new Claim(ClaimTypes.Role, "Administrator"),
  };

  var claimsIdentity = new ClaimsIdentity(claims, "AuthCookie");

  await HttpContext.SignInAsync(
      "AuthCookie",
      new ClaimsPrincipal(claimsIdentity));

  Logger.LogInformation("Signed in {user}", claimsIdentity.Name);

  return RedirectToAction(nameof(Index));
}