Features:
- two databases: food cards in the 1st tab and in the slot area
- select the food cards by clicking them in the 1st tab
- add the selected cards to the slot area
- remove the selected cards from the 1st tab
- when the card is unselected, remove it from the slot area and add it to the 1st tab
- when the user is inactive in 15 seconds, send the selected cards to the teacher (mobile) device
- if no cards are selected, remind to select at least one card after 15 seconds of inactivity
- when no cards are selected, also hide the slot area to show all the cards in the 1st tab
- when sending cards, give a notification about selected cards in the other device
- sending the cards works in both directions: both a pupil (tablet) and a teacher (mobile) device can select cards and send them to the other device