Fix curl command

Add explanation for app using app.import.

Author: kratiahuja

markdown/docs/addon-author-guide.md

@@ -217,6 +217,9 @@ modules it exports will not be available inside the app when running in
 the FastBoot environment. Make sure to guard against missing
 dependencies in that case.
 
+For apps trying to import third party libraries that are not compatible in Node, should
+create an in-repo addon within their app and follow the above guideline.
+
 ## Loading additional assets in FastBoot
 
 Often your addon may require to load third party libraries that are

markdown/intro.md

@@ -7,7 +7,7 @@ Only after the content has loaded do they start downloading JavaScript. Once fin
 And yes, this means the content in your Ember application is accessible to everyone, even if they have JavaScript turned off. It's even accessible to cURL—try it yourself:
 
 ```sh
-curl http://www.ember-fastboot.com
+curl 'http://localhost:4200/' -H 'Accept: text/html'
 ```
 
 For more information, see [the User Guide](/docs/user-guide)