Phalcon\Config\Adapter\Ini not found on command line application

I'm trying to set up a command line application, but I'm trying to reuse as much from the site's code as possible. Therefore, I'd like to import the ini configuration files that we use in the site. However, the following lines of code produces an error:

use Phalcon\Config\Adapter\Ini as ConfigIni;
$config = new ConfigIni(APP_PATH . 'app/config/default.ini');

The error I get:

PHP Fatal error:  Class 'Phalcon\Config\Adapter\Ini' not found in /mnt/dev-data/lex/360/app/cli.php on line 18

The same two lines in the site bootstrap work as expected, but when trying to call that bootstrap from the command line, it doesn't work either.

Is this the expected behavior of Phalcon or is this an error on our setup?

EDIT: I just found all Phalcon classes give a fatal error, so it's probably an incorrect configuration on our side.