Firestore security rules do not work.
Help me.
Document data of users/userid could not be read.

----------Security Rule------------

```
service cloud.firestore {
 match /databases/{database}/documents {
  match /users/{userId=**} {

  // Missing or insufficient permissions.
    allow read, write: if request.auth.uid == userId

  // this is work.
  //allow read, write: if request.auth != null

}

```

}
}

--------------main.js--------------------

```
import Vue from 'vue'
import Quasar from 'quasar'
import firebase from 'firebase'
import 'firebase/firestore'

Vue.config.productionTip = false
Vue.use(Quasar)

let app;
firebase.initializeApp({
  apiKey: "",
  authDomain: "",
  databaseURL: "",
  projectId: "",
  storageBucket: "",
  messagingSenderId: ""
})

firebase.auth().onAuthStateChanged(user=> {
  if (user) {
    let ref = firebase.firestore().collection('users').doc(user.uid)
    ref.get().then(snapshot=>{
      // Error !! : Missing or insufficient permissions.
    }
  }
  if(!app){
    Quasar.start(() => {
      app = new Vue({
        el: '#q-app',
        render: h => h(require('./App').default)
      })
    })
  }

})

```

firebase ^4.8.0
vue ^2.5.0

Apparently, require.auth.uid does not seem to work properly.
Where is there a mistake in me?