Thank you for your contribution to this book! I need to own the copyright for the book for publishing reasons.
I will make some money from the book, but it's not likely to be a huge amount. This site will continue to be freely available and I'll acknowledge all contributions in the printed book.
To confirm that you're ok with giving me your copyright, please include the phrase: "I assign the copyright of this contribution to Alex Gold".
If you have any questions, feel free to raise them in the pull request or send me an email.