code: function pullImage(docker, image, options) {
    return new Promise(function(accept, reject) {
      docker.pull(image).then(function(stream) {
        var pullStatusStream = new PullStatusStream();
        stream.pipe(pullStatusStream);
  
        pullStatusStream.on('data', function(value) {
          debug('pull image', value.toString());
        });
  
        pullStatusStream.once('error', reject);
        pullStatusStream.once('end', accept);
      });
    });
  }
docs: Returns a promise for the result of the image pull (no output stream).
  
  @param {DockerodePromise} docker wrapper.
  @param {String} image docker image name.
  @param {Object} [options] docker pull options.
  @return Promise