Fixed docs for setting up with express

In connect-sequelize.js:20 the passed argument is used as:

module.exports = function SequelizeSessionInit(express) {
    var Store = express.Store || express.session.Store;
...
}
Fixed sequelize callback signature.

It might be a bug in sequelize, but currently when with findOrCreate success
callback is passed a function with one argument it clamps both arguments
(model, isCreated) into an array and pass that instead.

e.g. this:
findOrCreate(...).success(function callback(model) {console.log(model)})
outputs:
[Object object, true]
Merge branch 'findOrCreate-fix' of https://github.com/shadone/connect-sequelize