Features

Would love to see the new features from Firestore integrated into AngularFire. Mainly "Aggregation Queries".

### Version info

**Angular:**

**Firebase:**

**AngularFire:**

**Other (e.g. Ionic/Cordova, Node, browser, operating system):**

### How to reproduce these conditions

**Failing test unit, Stackblitz demonstrating the problem**

**Steps to set up and reproduce**

**Sample data and security rules**

### Debug output

** Errors in the JavaScript console **

** Output from `firebase.database().enableLogging(true);` **

** Screenshots **

### Expected behavior

### Actual behavior

No files, tests, or entry points are identified. Start by reviewing AngularFire's Firestore integration and Firebase's Aggregation Queries documentation; done would require a defined AngularFire API for the requested feature along with coverage for its behavior.

Written by the indexing model from the issue text.