instance method parse!

# File railties/lib/commands/plugin.rb, line 836
    def parse!(args)
      options.parse!(args)
      root = @base_command.environment.root
      cd root
      args = Dir["vendor/plugins/*"].map do |f|
        File.directory?("#{f}/.svn") ? File.basename(f) : nil
      end.compact if args.empty?
      cd "vendor/plugins"
      args.each do |name|
        if File.directory?(name)
          puts "Updating plugin: #{name}"
          system("svn #{$verbose ? '' : '-q'} up \"#{name}\" #{@revision ? "-r #{@revision}" : ''}")
        else
          puts "Plugin doesn't exist: #{name}"
        end
      end
    end