message: Add an example of sharing Auth across stacks
diff: @@ -191,6 +191,38 @@ auth.attachPermissionsForUnauthUsers([
  ]);
  ```
  +### Sharing Auth across stacks
  +
  +You can create the Auth construct in one stack, and attach permissions in other stacks. To do this, expose the Auth as a class property.
  +
  +```js {8} title="lib/AuthStack.js"
  +const auth = new Auth(this, "Auth", {
  + cognito: true,
  +});
  +
  +this.auth = auth;
  +```
  +
  +Then pass the Auth to a different stack.
  +
  +```js {2} title="lib/index.js"
  +const authStack = new AuthStack(app, "auth");
  +new ApiStack(app, "api", { auth: authStack.auth });
  +```
  +
  +Finally, attach the permissions.
  +
  +```js title="lib/ApiStack.js"
  +const api = new Api(this, "Api", {
  + routes: {
  + "GET /notes": "src/list.main",
  + "POST /notes": "src/create.main",
  + },
  +});
  +
  +props.auth.attachPermissionsForAuthUsers([api]);
  +```
  +
  ### Upgrading to v0.12.0
  The v0.12.0 release of the Auth construct includes a small breaking change. You might be impacted by this change if:
  