public ActionResult ExternalLoginConfirmation(RegisterExternalLoginModel model, string returnUrl)
        {
            string provider = null;
            string providerUserId = null;

            if (User.Identity.IsAuthenticated || !OAuthWebSecurity.TryDeserializeProviderUserId(model.ExternalLoginData, out provider, out providerUserId))
            {
                return RedirectToAction("Manage");
            }

            if (ModelState.IsValid)
            {
                // Insert a new user into the database
                using (UsersContext db = new UsersContext())
                {
                    UserProfile user = db.UserProfiles.FirstOrDefault(u => u.UserName.ToLower() == model.UserName.ToLower());
                    // Check if user already exists
                    if (user == null)
                    {
                        // Insert name into the profile table
                        db.UserProfiles.Add(new UserProfile { UserName = model.UserName });
                        db.SaveChanges();

                        OAuthWebSecurity.CreateOrUpdateAccount(provider, providerUserId, model.UserName);
                        OAuthWebSecurity.Login(provider, providerUserId, createPersistentCookie: false);

                        return RedirectToLocal(returnUrl);
                    }
                    else
                    {
                        ModelState.AddModelError("UserName", "User name already exists. Please enter a different user name.");
                    }
                }
            }

            ViewBag.ProviderDisplayName = OAuthWebSecurity.GetOAuthClientData(provider).DisplayName;
            ViewBag.ReturnUrl = returnUrl;
            return View(model);
        }