CHEF-18 deprecation + other problems

I'm trying to install CHEF for the first time.

I'm using a MAC as my development machine, deploying to Ubuntu.
chef generate repo WWW // seems to work ok
cd WWW
knife zero bootstrap x.x.x.x --ssh-user root --node-name WWW

results in

WARN: Deprecation CHEF-18 ...
Starting local-mode server in deprecated socket mode

It wants rbnacl, rbnacl-libsodium, crypt-pbkdf

How do I fix this problem? How/where do I install these gems?

Thanks!

Joe

Run chef exec gem install for each