execute seems to require roles (re: readme on security/keys)

[vcavallo]

This section of the readme:

namespace :app do
  task :update_rvm_key do
    execute :gpg, "--keyserver hkp://keys.gnupg.net --recv-keys D39DC0E3"
  end
end
before "rvm1:install:rvm", "app:update_rvm_key"

Fails with NoMethodError: undefined methodexecute' for main:Object. Wrapping theexecute` line in

roles(:all) do
  execute :gpg, "--keyserver hkp://keys.gnupg.net --recv-keys D39DC0E3"
end

appears to fix it.

[vcavallo]

i've now noticed this pull request #63 which is about the same problem.