code: function readPromise(file, defaultContent){
  	return new Promise(function(resolve, reject){
  		if ( exists(file) ) {
  			fs.readFile(file, 'utf-8', (err, data) => err ? reject(err) : resolve(data));
  		}else{
  			defaultContent === undefined ? reject('file not found: ' + file) : resolve(defaultContent);
  		}
  	});
  }
docs: ---------------------------------