code: function firstCommit(dir, cb) {
    if (typeof dir === 'function') {
      return firstCommit(process.cwd(), dir);
    }
    if (typeof cb !== 'function') {
      throw new TypeError('expected callback to be a function');
    }
  
    lazy.git(dir).log(function(err, history) {
      if (err) return cb(err);
  
      history.sort(function(a, b) {
        return b.date.localeCompare(a.date);
      });
  
      cb(null, history[history.length - 1]);
    });
  }
docs: Asynchronously get the first commit from a git repository.
  
  ```js
  firstCommit('foo/.git', function(err, commit) {
  if (err) return console.log(err);
  // do stuff with commit
  });
  ```
  @param {String} `cwd` current working directory
  @param {Function} `callback`
  @return {Object}
  @api public