title: Most efficient way to increment a value of everything in Firebase
body: <p>Say I have entries that look like this:</p>
  
  <p><a href="https://i.stack.imgur.com/jmRcZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jmRcZ.png" alt="Firebase Image"></a></p>
  
  <p>And I want to increment the <code>priority</code> field by 1 for every Item in the list of Estimates.</p>
  
  <p>I can grab the estimates like this:</p>
  
  <pre><code>var estimates = firebase.child('Estimates');
  </code></pre>
  
  <p>After that how would I auto increment every Estimates priority by 1?</p>