Updated readme instructions

Author: nicolasgarnier

firestore/README.md

@@ -30,7 +30,7 @@ Follow these steps to setup and run the quickstart:
     ```bash
     firebase serve
     ```
- 1. As indicated, open [http://localhost:5000] in your browser and try out the app.
+ 1. As indicated, open [http://localhost:5000](http://localhost:5000) in your browser and try out the app.
 
 ## Support