Upgrade Capistrano and install gems to deploy the Rails version
cap install
Upgrade Capistrano 2 PHP deployment files to Capistrano 3 multistage
Upgrade to Ruby 2
Use RVM

This seems like a real dick move to have to set the RVM Ruby version
in the repo twice (once here and once in .ruby-version), alas
Switch Capistrano RVM gem to one that works like the 2.x one did
Ignore bundler config