After you log in to your account, go to the navigation bar and go to “Loyalty Cards.” Tap the red “+” at the bottom of screen and it will open up the list of loyalty cards.
Tap “Add other card” to add a card which isn't listed.
Now all you need to do is add the name and card number. If you like, add a customized color to remember the card. When you are finished simply hit the button that says, “Add Card”.