function handleNewItemSubmit()
Listen for a mouse click on the 'add item' submit button;
Add the entered name into our global varialbe STORE with checked attribute set to 'false'
Call renderShoppingList to refresh the grocery list

function handleItemCheckClicked()
Listen for a mouse click on the 'check' button of the item
Assign the css class that styles a strike-through on the item name
Call renderShoppingList to refresh the grocery list

Delete Items
Listen for a mouse click on the 'delete' button
Delete this item from our array 'STORE'
Call renderShoppingList to refresh the grocery list