写一份需求说明，shape up 需要具备五点。问题、胃口、方案、坑、不做。

There are five ingredients that we always want to include in a pitch:

Problem — The raw idea, a use case, or something we’ve seen that motivates us to work on this

Appetite — How much time we want to spend and how that constrains the solution

Solution — The core elements we came up with, presented in a form that’s easy for people to immediately understand

Rabbit holes — Details about the solution worth calling out to avoid problems

No-gos — Anything specifically excluded from the concept: functionality or use cases we intentionally aren’t covering to fit the appetite or make the problem tractable