title: What exactly classNameBindings is doing?
body: <p>I'm new to Ember and I'm following a tutorial which contains code for component: </p>
  
  <pre><code>export default Ember.Component.extend({
    tagName: 'li',
    classNameBindings: ['editing'],
    editing: false,
    actions: {
      editTodo() {
        this.toggleProperty('editing');
      }
    }
  });
  </code></pre>
  
  <p>I don't understand what <code>classNameBindings</code> is doing. From documentation I've learned that <code>classNameBindings is a list of properties of the view to apply as class names</code>, but I also have <code>editing</code> property on the component. How existence of this property effects this process of creating <code>class names</code>?</p>
  
  <p>Thank you for any help :-)</p>