public function deploy()
    {
        $pullRequest = getenv('TRAVIS_PULL_REQUEST');
        $branch = getenv('TRAVIS_BRANCH');

        if ((int) $pullRequest >= 1) {
            die('Not deploying pull requests.' . PHP_EOL);
        }

        if (!array_key_exists($branch, $this->branches)) {
            die('Branch ' . $branch . ' has no environment to deploy to.' . PHP_EOL);
        }

        $environment = $this->branches[$branch];

        echo 'Downloading Deployer.phar...' . PHP_EOL;
        passthru('wget http://deployer.org/deployer.phar');

        echo 'Deploying...' . PHP_EOL;
        $deployCommand = 'php deployer.phar deploy';
        $deployCommand .= ' ' . $environment;
        $deployCommand .= $this->verbose ? ' -vvv' : '';
        passthru($deployCommand);
    }