Lidl has their own IT company that is not mentioned in the article as far as I can see: https://it.schwarz/ (linked from the "Digits" page, though)
And their in-store discounts require you to have an Android or Apple device and install their proprietary app on it from Google Play or iTunes, and sign up for an account using your e-mail address and personal cellphone number (landlines and non-geographical numbers are disallowed). It also collects your data and sends it to Google and Facebook.
This is the worst IT of any store I've seen.