Sorry about that everybody! The “devtalk.com” discount code can now be applied to this book.
On the plus side, the Devtalk community gets to hear about all our new books before we announce them publicly anywhere else. On the downside, the Devtalk community (and, in this case, the ElixirForum community) get to deal with all our bugs before anybody else, too. 
Hope you enjoy the book and please be sure to share your feedback with @svilen!