Deployer\Deployer::addDefault PHP Method

    public static function addDefault($name, $array)
    {
        if (self::hasDefault($name)) {
            $config = self::getDefault($name);
            if (!is_array($config)) {
                throw new \RuntimeException("Configuration parameter `{$name}` isn't array.");
            }
            self::setDefault($name, array_merge($config, $array));
        } else {
            self::setDefault($name, $array);
        }
    }

/**
 * Merge new config params to existing config array.
 *
 * @param string $name
 * @param array $array
 */
function add($name, $array)
{
    if (Context::get() === false) {
        Deployer::addDefault($name, $array);
    } else {
        Context::get()->getEnvironment()->add($name, $array);
    }
}