The “report erratum” hyperlink at the bottom of each page of the PDF takes us to
https://pragprog.com/titles/liveview/programming-phoenix-liveview/
“discuss” takes us to https://pragprog.com/
Both, I think, should bring us to this forum.
Oh interesting, thanks for bringing that up. I’ll pass that along to the publisher 
@asibbald I will check on the links you mention for errata and discussion in the PDF. I think the current intention is for both links to take you to the book’s page on PragProg, where you then find the link to this forum. Perhaps because that way if we move errata or discussion elsewhere, we just change the link on the book’s webpage, and don’t have to change the ebook footer link.