Rewrite the 'ppa' dep to use `add-apt-repository` so the repo's key is added.
Rewrite the 'ppa' dep to use `add-apt-repository` so the repo's key is added.

* Also, check for existence by checking for the apt list, which will catch the case where the ppa has been added but `apt-get update` hasn't been run yet.

victorklos/babushka,victorklos/babushka,victorklos/babushka