Signals don't work

[Cally99]

When you publish book signal doesn't print book and author

[nightwarriorftw]

Hey @Cally99,
Thanks for reporting this issue. Have pushed a small fix for it.

Problem is with transaction.on_commit we usually pass a callback but instead earlier we were simply calling method. Passing the book_published signal as a callback fixed the issue.
Let me know if you still face any issues :)