public function createPullRequest($headBranch, $baseBranch = 'master')
    {
        /** @var PullRequest $api */
        $api = $this->githubClient->api('pull_request');
        $api->create($this->organization, $this->project, array(
                'base'  => $baseBranch,
                'head'  => sprintf('%s:%s', $this->username, $headBranch),
                'title' => $this->pullRequestTitle,
                'body'  => $this->pullRequestMessage
            )
        );
    }