def add_version_option(task = command, *wrap)
    OptionParser.accept Gem::Requirement do |value|
      Gem::Requirement.new value
    end

    add_option('-v', '--version VERSION', Gem::Requirement,
               "Specify version of gem to #{task}", *wrap) do
                 |value, options|
      options[:version] = value
      options[:prerelease] = true if value.prerelease?
    end
  end
#
Add the --version option to the option parser.