title: How to create blank firebase references
body: <p>Lets say I have a firebase and I want to add Book and Chapter objects to the root node to look like this.</p>
  
  <pre><code>example: {
    books: {
      book_id: {//book object}
    }
    chapters: {
      chapter_id: {//chapter object}
    }
  }
  </code></pre>
  
  <p>The specific problem I am having is how do I have a blank chapters reference without objects underneath it.  Like the following</p>
  
  <pre><code>example: {
    books: {
      book_id: {//book object}
    }
    chapters: {
      //this has no objects underneath it
    }
  }
  </code></pre>
  
  <p>You cannot just leave it blank in firebase or the chapters reference will disappear.  I thought maybe I could just add a .keep or something to the chapters reference, but that did not work either.  Also, if I delete all of the chapter objects from underneath the chapters reference it deletes the chapters reference.  </p>
  
  <p>The main reason I want to have these blank references is so that I can delete all of the objects from a certain reference, but then keep the reference in firebase so I can write more objects to it.  So if there is another way of accomplishing that using firebase/emberFire it would be nice to know.</p>