debugging rake task error

testing for issue jwhitley#247

lib/tasks/requirejs-rails_tasks.rake

@@ -163,7 +163,7 @@ OS X Homebrew users can use 'brew install node'.
 
         # Compute the digest based on the contents of the compiled file, *not* on the contents of the RequireJS module.
         file_digest = ::Rails.application.assets.file_digest(built_asset_path.to_s)
-        hex_digest = file_digest.unpack("H*").first
+        hex_digest = file_digest.hexdigest
         digest_name = asset.logical_path.gsub(path_extension_pattern) { |ext| "-#{hex_digest}#{ext}" }
 
         digest_asset_path = requirejs.config.target_dir + digest_name