title: I want to create firebase security rules for my flutter app. I am using cloud firestore and I am using google sign in without firebase auth
body: <p>If I use firebase.auth like this,</p>
  <p><code>allow read,write : if request.auth != null;</code></p>
  <p>It says not enough permissions in debug console...because I am not using firebase auth and want to know that is there any workaround for google sign in without firebase auth. I am new to firebase. Thanks</p>