config.rb

namespace :deploy do
    desc <<-DESC 
    Checks the latest version of the libraries 
    to make sure we're not deploying our code 
    onto a platform which is not prepared for it
    DESC
    task :checkdeps do
        required_libs.each do | appname,version |
            current_version = capture("cat /var/www/#{appname}/application/config/version").strip()
            if version.to_f() > current_version.to_f() then
                error = CommandError.new("Deployed version of #{appname} (#{current_version}) does not match required version (#{version})")
                raise error
            end
        end
    end
end