Added options to fix #490. Now you can use a connection string (i.e. Heroku) and…

… options can be passed as second parameter.

lib/sequelize.js

@@ -47,7 +47,8 @@ module.exports = (function() {
     var urlParts
     options = options || {}
 
-    if (arguments.length === 1) {
+    if (arguments.length === 1 || (arguments.length === 2 && typeof username === 'object')) {
+      options = username || {}
       urlParts = url.parse(arguments[0])
       database = urlParts.path.replace(/^\//,  '')
       dialect = urlParts.protocol