Create products cart feature #4
Description
Create products cart feature that handles:
- showing count and price of each individual product [done in Created products cart feature #16]
- summing up products prices and their amount [done in Created products cart feature #16]
- keeping Cart state between app reloads [done in Created products cart feature #16]
- discount code
- making order (associate with payment feature) [done in Implemented basic integration with PayU API #27, Finish order process #61]