title: How to create auto incremented key in Firebase?
body: <p>I was wondering if we could create auto increment ID's(Keys) in Firebase like we have in SQL! </p>
  
  <p>I was wanting to create a structure like this </p>
  
  <pre><code>rules:
    Line1:
      1: Smith
      2: Alex
      3: Hello
    Line2:
      1: Brown
      2: Michael
  </code></pre>
  
  <p>So lets say if I want to add "Erik" to Line 1 it should do it like this </p>
  
  <pre><code>Line1:
      1: Smith
      2: Alex
      3: Hello
      4: Erik
  </code></pre>
  
  <p>Is it possible have structure like that? </p>
  
  <p>I do know we have </p>
  
  <blockquote>
    <p>push()</p>
  </blockquote>
  
  <p>and </p>
  
  <blockquote>
    <p>childByAutoId()</p>
  </blockquote>
  
  <p>but this does not fit for my problem.  I am working with Swift iOS just. </p>