code: function computeChecksum(filename) {
  	var contents = fs.readFileSync(filename);
  
  	var hash = crypto
  		.createHash('md5')
  		.update(contents)
  		.digest('base64')
  		.replace(/=+$/, '');
  
  	return hash;
  }
docs: Compute checksum for a file.
  
  @param {string} filename The absolute path to a filename.
  @return {string} The checksum for `filename`.