Fix: user re-create order still show paid bug

Change: update paid info after successful checkout; Fix: check notification effective duration (5 min) (#17)

[yulunt] remove unused url and add model delete casacade (#16)

Develop order date (#15)

Bunch Order (#14)

[yulunt] complete interface of backend to handle payment, internal logic is pending (#13)

Get user order (#12)

[yulunt] update delete pickup_locations http response status code

[yulunt] update dish model (#11)

Develop tab3 (#10)

complete order APIs (#9)

Add: modify rate score of dish API (#6)

[yulunt] fix IndexError bugs in both location and notificaiton model (#5)

Develop complete notification and location (#4)

Develop data model (#2)