title: firebase $add() .push() .set()
body: <p>I am using firebase, and angularfire.
  there are so many ways to do CRUD with the Firebase Api
  actually, I still don't get what is specific difference for using</p>
  
  <ul>
  <li>$add with $firebaseArray</li>
  <li>.push() method</li>
  <li>.set() method</li>
  </ul>
  
  <p>I think they are technically same, I prefer to use .set method() without knowing the exact reason, why I'd using that. is there any specific reason to not use it? what is exactly $firebaseArray did? if we could just declare basic reference variable.</p>
  
  <p>in this case:</p>
  
  <pre><code>var usersRef = Ref.child('users');
  
    $scope.createUser = function() {
      $scope.userRef.child($id).set({
         name: name
             });
        };
  </code></pre>
  
  <p>or</p>
  
  <pre><code>$scope.data = $firebaseArray(Ref.child('users'));
  
  $scope.createUser = function() {
    $scope.data.child($id).$add({
      name: name
    });
   };
  </code></pre>
  
  <p>thank you.</p>