Fix postgres example

Author: Thom Seddon

examples/postgresql/model.js

@@ -77,7 +77,7 @@ model.saveRefreshToken = function (refreshToken, clientId, userId, expires, call
 	pg.connect(connString, function (err, client, done) {
 		if (err) return callback(err);
 		client.query('INSERT INTO oauth_refresh_tokens(refresh_token, client_id, user_id, ' +
-				'expires) VALUES ($1, $2, $3, $4)', [accessToken, clientId, userId, expires],
+				'expires) VALUES ($1, $2, $3, $4)', [refreshToken, clientId, userId, expires],
 				function (err, result) {
 			callback(err);
 			done();