Token accessToken = oauthService.getAccessToken(requestToken, new Verifier(verifier));
// Fetch user oAuthAccount
OAuthAccount oAuthAccount = oauthProvider.getUserAccount(accessToken.getToken(), accessToken.getSecret());
// Retrieve existing oAuthAccount from profile
AuthAccount account = AuthAccount.find(provider, oAuthAccount.getOAuthLogin());
if (account != null) {
onSuccessfulAuthentication(account.member.login);
} else {