Updated Read me - Added reference to Ionic2

Updated Link title for AngularFire2 with Ionic2

Author: mukesh51

README.md

@@ -58,4 +58,4 @@ productive with AngularFire2.
 3. [Retreiving data as lists - FirebaseListObservable](docs/3-retrieving-data-as-lists.md)
 4. [Querying lists](docs/4-querying-lists.md)
 5. [User Authentication - FirebaseAuthentication](docs/5-user-authentication.md)
-6. [Ionic2 - Authenticating with AngularFire2](docs/Auth-with-Ionic2.md)
+6. [Using AngularFire2 with Ionic 2](docs/Auth-with-Ionic2.md)