Document Order lifecycle

[peelar]

I think we should add a “Guides” (or rather a “concept”) page for Orders in Saleor.

When you search for “order” in the docs search, the results are “queries” order and “objects” order, both technical reference-type resources. I think we should have something more general.

The article would be the most useful for me if it described the order lifecycle (with f.e. a state machine for all the states the order can be in).

We currently have the following order events:

• ORDER_CREATED
• ORDER_CONFIRMED
• ORDER_FULLY_PAID
• ORDER_UPDATED
• ORDER_CANCELLED
• ORDER_EXPIRED
• ORDER_FULFILLED
• ORDER_REFUNDED
• ORDER_FULLY_REFUNDED
• ORDER_METADATA_UPDATED
• DRAFT_ORDER_CREATED
• DRAFT_ORDER_UPDATED
• DRAFT_ORDER_DELETED

We should document how an order progresses from one state to another and what are the implications of that (e.g., a fulfilled order can’t be canceled).