I just went through a manual install on DietPi / Debian Unstable, and found that the manual needed some improving, this method works, whereas following the original manual was not a success for me.
The only line I would say I am unsure about is this one:
"Give the user permissions: `chown -R recipes:www-data /var/www/recipes`"
As I am not sure whether these permissions are necessary for this to work.
Hope this is useful, let me know if I can make further improvements.