update README

Author: choru-k

README.md

@@ -312,6 +312,16 @@ firestack.deleteUser()
 .catch(err => console.error('There was an error - Now you are trapped!'))
 ```
 
+#### getToken()
+
+If you want user's token, use `getToken()` method.
+
+```javascript
+firestack.getToken()
+.then(res => console.log(res.token))
+.catch(err => console.error('error'))
+```
+
 #### signOut()
 
 To sign the current user out, use the `signOut()` method. It accepts no parameters

ios/Firestack/Firestack.m

@@ -338,7 +338,7 @@ @implementation Firestack
                              withUser:user];
             callback(@[err]);
         } else {
-            callback(@[[NSNull null], @{@"result": token}]);
+            callback(@[[NSNull null], @{@"token": token}]);
         }
     }];
 }