code: function done(err, content) {
              if (err) return cb(err);
  
              var code = JSON.parse(self.square.package.source)
                , current = bundle.version || self.version(bundle.meta.content)
                , source;
  
              code.bundle[key].version = version;
              bundle.version = version;
              bundle.content = content;
  
              // now that we have updated the shizzle, we can write a new file
              // also update the old source with the new version
              source = JSON.stringify(code, null, 2);
              self.square.package.source = source;
  
              try {
                async.parallel([
                    async.apply(fs.writeFile, self.square.package.location, source)
                  , async.apply(fs.writeFile, bundle.meta.location, content)
                ], function (err, results) {
                  self.square.logger.notice(
                      'sucessfully updated %s from version %s to %s'
                    , key
                    , current.grey
                    , version.green
                  );
  
                  cb(err);
                });
              } catch (e) { err = e; }
            }
docs: Handle file upgrades.
  
  @param {Mixed} err
  @param {String} content
  @api private