Update default port (#295)

Background:
    The README specifies that the server runs on port 5000, but it runs on 5001.

    Modifications:
    Update README to specify port 5001.

    Result:
    The port specified by the README is correct when booting the default getting-started server.

Author: zackisaacs

README.md

@@ -15,7 +15,7 @@ $ npm install
 $ npm start
 ```
 
-Your app should now be running on [localhost:5000](http://localhost:5000/).
+Your app should now be running on [localhost:5001](http://localhost:5001/).
 
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