This is a simple app to try Redux.
- the badge of the counter must indicate the total number of items currently in cart
- the total amount must be correct
- the buttons "add"/"remove" must be functional
- all the buttons must be disabled when it's logical for them to be so
- enable the "in stock items" filter
- the app must fill it's initial state from the mocked API
- the cart must be sent via the mocked API
- errors must be handled and displayed to the user