class GemHadar

adding gem_files to the package_files attribute of the Gem::PackageTask.
tar files should be created. It also includes the files to be packaged by
a Gem::PackageTask with the current gem specification, and specifies that
This method configures a task that creates a package directory, initializes

The package_task method sets up a Rake task for packaging the gem.

def package_task
  clean 'pkg'
  Gem::PackageTask.new(gemspec) do |pkg|
    pkg.need_tar      = true
    pkg.package_files += gem_files
  end
end