donna command line fails when output directory doesn't exist

[technicalpickles]

I did an npm install donna, then tried:

$ donna -o donna src
fs.js:427
  return binding.open(pathModule._makeLong(path), stringToFlags(flags), mode);
                 ^
Error: ENOENT, no such file or directory 'donna/metadata.json'
  at Object.fs.openSync (fs.js:427:18)
  at Object.fs.writeFileSync (fs.js:966:15)
  at writeMetadata (/opt/boxen/nodenv/versions/v0.10.21/lib/node_modules/donna/src/donna.coffee:106:6)
  at Object.main (/opt/boxen/nodenv/versions/v0.10.21/lib/node_modules/donna/src/donna.coffee:47:3)
  at Object.<anonymous> (/opt/boxen/nodenv/versions/v0.10.21/lib/node_modules/donna/bin/donna:3:25)
  at Module._compile (module.js:456:26)
  at Object.Module._extensions..js (module.js:474:10)
  at Module.load (module.js:356:32)
  at Function.Module._load (module.js:312:12)
  at Function.Module.runMain (module.js:497:10)
  at startup (node.js:119:16)
  at node.js:901:3

$ mkdir donna
$ donna -o donna src
$ echo $?
0

I think either the output directory should be created, or at least check for its presence before creating. I could go either way.