docs: update

docs/site/migration/auth/example.md

@@ -179,6 +179,9 @@ in the application constructor:
 {% include code-caption.html content="src/application.ts" %}
 
 ```ts
+// Add this line to import the component
+import {JWTAuthenticationComponent} from './components/jwt-authentication';
+
 export class AccessControlApplication extends BootMixin(
   ServiceMixin(RepositoryMixin(RestApplication)),
 ) {
@@ -336,7 +339,32 @@ Since the model and policy are already covered in section
 files are defined in folder
 [fixtures/casbin](https://github.com/strongloop/loopback-next/blob/master/examples/access-control-migration/fixtures/casbin).
 
-5. Casbin persistency and synchronize(2nd Phase implementation, TBD)
+5. Mount the casbin authorization system as a component
+
+The casbin authorizer, voter and enforcers above are packed under component
+'src/components/casbin-authorization'. You can export their bindings in a
+[component file](https://github.com/strongloop/loopback-next/blob/master/examples/access-control-migration/src/components/casbin-authorization/casbin-authorization-component.ts)
+and mount the component in the application constructor:
+
+{% include code-caption.html content="src/application.ts" %}
+
+```ts
+// Add this line to import the component
+import {CasbinAuthorizationComponent} from './components/casbin-authorization';
+
+export class AccessControlApplication extends BootMixin(
+  ServiceMixin(RepositoryMixin(RestApplication)),
+) {
+  constructor(options: ApplicationConfig = {}) {
+    // ...
+    // Add this line to mount the casin authorization component
+    this.component(CasbinAuthorizationComponent);
+    // ...
+  }
+}
+```
+
+6. Casbin persistency and synchronize(2nd Phase implementation, TBD)
 
 This will be supported at the 2nd phase of implementation. The plan is to have
 model or operation hooks to update the casbin policies when new data created. It