fix(readme): Fix readme to reflect correct port (#832)

The local port changed from 9000 to 9001 in #830 but the repo readme was out of date even before that.

Author: lobsterkatie

README.md

@@ -17,7 +17,7 @@ To run the local webserver:
 $ bin/server
 ```
 
-This will run Bundler to install all the necessary dependencies and then run a webserver at http://localhost:4000/.
+This will run Bundler to install all the necessary dependencies and then run a webserver at http://localhost:9001/.
 
 [jekyll]: https://jekyllrb.com/
 [ruby]: https://www.ruby-lang.org/