Fixed 404 in readme

On the current README - https://github.com/martinwolf/GiveMeSomethingToCode/blob/master/README.md

The link for GiveMeSomethingToCode gives a 404 (http://theamazingweb.net/givemesomethingtocode)

I updated the link to point to the right page: http://theamazingweb.net/2013/04/05/give-me-something-to-code/