title: How to add, update and list data into firebase using js
body: <p>I am doing my first application using react native and firebase so I know how to configure like this</p>
  
  <pre><code>var config = {
    apiKey: "&lt;API_KEY&gt;",
    authDomain: "&lt;PROJECT_ID&gt;.firebaseapp.com",
    databaseURL: "https://&lt;DATABASE_NAME&gt;.firebaseio.com",
    storageBucket: "&lt;BUCKET&gt;.appspot.com",
  };
  firebase.initializeApp(config);
  </code></pre>
  
  <p>But I don't know how to list add or update data somebody can help me I've tried this</p>
  
  <pre><code>firebase.database().ref('users/' + userId).set({
      username: name,
      email: email,
      profile_picture : imageUrl
  });
  </code></pre>