fix(docs): Ionic build (angular#1143)

danielsogl · davideast · commit db75c45dd239 · 2017-09-06T09:50:37.000-06:00
see ionic-team/ionic-app-scripts#1001
diff --git a/docs/Auth-with-Ionic3-Angular4.md b/docs/Auth-with-Ionic3-Angular4.md
@@ -163,7 +163,7 @@ Install angularfire2 and firebase by executing the following command in your pro
 
 ```ts
 
-C:\projects\auth-ng4-ionic3-af2>npm install angularfire2 firebase --save
+C:\projects\auth-ng4-ionic3-af2>npm install angularfire2 firebase promise-polyfill --save
 
 ```
 
