FIX: Support ember app routing to topics with only slugs

test/javascripts/helpers/create-pretender.js.es6

@@ -34,6 +34,10 @@ export default function() {
       }
     });
 
+    this.get("/t/id_for/:slug", function() {
+      return response({id: 280, slug: "internationalization-localization", url: "/t/internationalization-localization/280"});
+    });
+
     this.get("/404-body", function() {
       return [200, {"Content-Type": "text/html"}, "<div class='page-not-found'>not found</div>"];
     });