gistfile1.cs

                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);
                    }
                }