Add example of creating a router

Documentation/Books/Manual/Foxx/Migrating2x.mdpp

@@ -357,10 +357,35 @@ afterRemove(doc);
 
 !SECTION Controllers vs routers
 
-Foxx Controllers have been replaced with [Routers](Router/README.md). This is more than a cosmetic change as there are significant differences in behaviour:
+Foxx Controllers have been replaced with [routers](Router/README.md). This is more than a cosmetic change as there are significant differences in behaviour:
 
 Controllers were automatically mounted when the file defining them was executed. Routers need to be explicitly mounted using the `module.context.use` method. Routers can also be exported, imported and even nested. This makes it easier to split up complex routing trees across multiple files.
 
+Old:
+
+```js
+'use strict';
+const Foxx = require('org/arangodb/foxx');
+const ctrl = new Foxx.Controller(applicationContext);
+
+ctrl.get('/hello', function (req, res) {
+  // ...
+});
+```
+
+New:
+
+```js
+'use strict';
+const createRouter = require('org/arangodb/foxx/router');
+const router = createRouter();
+module.context.use(router);
+
+router.get('/hello', function (req, res) {
+  // ...
+});
+```
+
 Some general changes in behaviour that might trip you up:
 
 * When specifying path parameters with schemas Foxx will now ignore the route if the schema does not match (i.e. `/hello/foxx` will no longer match `/hello/:num` if `num` specifies a schema that doesn't match the value `"foxx"`). With controllers this could previously result in users seeing a 400 (bad request) error when they should instead be served a 404 (not found) response.