title: how to pass auth token in firebase database() 'on' method to access database
body: <p>I have set my firebase database rules to <code>"auth != null"</code> and to access the database through http request I can pass the auth Token with the api endpoint url like <code>http.get('url?auth=&lt;auth-token&gt;')</code>. But I want to access the firebase database through firebase SDK. </p>
  
  <pre><code>    firebase.database().ref('users'+ userId).on('value',(snapShot)=&gt;{
          this.setState({user: snapShot.val()});
      }) 
  </code></pre>
  
  <p>Here I am not getting any response because my database rule is set to <code>"auth != null"</code>. So how can I pass the auth detail in this request.</p>