﻿Write a SpacetimeDB backend module in Rust that defines one table and a reducer that inserts a row.

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

REDUCERS
- insert_user: given id:i32, name:String, age:i32, active:bool, insert exactly one row into user
  - (id=id, name=name, age=age, active=active)
