Bundle exec magic on Capistrano deploys

Today the deploy failed, with the helpful message “You have already activated rake 0.9.2, but your Gemfile requires rake 0.8.7. Using bundle exec may solve this.”  Rake 0.9.2 somehow go installed on our production server.  I checked my Gemfile and, yes, I had ‘0.8.7’ specified. It looked like I could add bundler/capistrano to my deploy.rb file, but that seemed to change too many things.. so I just added

set :rake, "bundle exec rake"

and that did the trick. Magic ;)