﻿Write a SpacetimeDB backend module in Rust that defines one table and a reducer that performs insert, update, and delete in one call.

TABLE
- user
  - Struct: User
  - Fields:
    - id: i32 (primary key)
    - name: String
    - age: i32
    - active: bool

REDUCERS
- crud: perform these steps in order
  - insert (id=1, name="Alice", age=30, active=true)
  - insert (id=2, name="Bob",   age=22, active=false)
  - update (id=1, name="Alice2", age=31, active=false)
  - delete id=2
