Fixed code to new version of express

[Darker]

I got this example to work, at least as far as authenticating user is concerned. Usage of express was grossly outdated.

[mattandrews]

Thanks for doing this – it might be worth adding a note above this code to specify the dependencies required, eg:

npm install --save express fbgraph method-override body-parser errorhandler pug

[criso]

thanks! - I added the npm line as well :)