Dead links to Github organization

[yann-eugone]

Hi there, just got the book, seems promising :)

There is few links wired to https://github.com/dddinphp which points to nothing anymore.
I believe this should have been rewired to https://github.com/dddshelf.

[StewPoll]

Just thought I'd comment here to saying these are still broken.

Every single link in this section points to /dddinphp instead of /dddshelf

The only one of these links that works, is the last link to the issues, which correctly redirects here.