Fix: Code and database did not match. Demo and code did not match

I've removed the email column from the code to match the databasestructure given in the documentatio.
I also changed so that the request for getting the information about the user will be sent and listened via POST. Previously it was sent as POST but listened as GET.

Thanks for a great example of a Single Sign On. Easy to understand and works just fine. Well... it works now after some minor changes.