Create Dynamic ng-models for firebase use | ionic | firebase | angularjs - angularjs

Question

I'm trying to make an app where users can tag other registered users in a post.
So the idea is if the user creates a new post. there is an ng-repeat for all the users available and for each of them a checkbox is created.
After the users are checked they have to be stored with the post in firebase.
Now i cant seem to figure out how to dynamically add properties to my firebase push
<div class="list">
<label class="item item-input item-stacked-label">
<span class="input-label">Titel</span>
<input type="text" placeholder="Titel" ng-model="formData.title">
</label>
<label class="item item-input item-stacked-label">
<span class="input-label">Beschrijving</span>
<input type="text" placeholder="Kaarten voor... etc" ng-model="formData.description">
</label>
<label class="item item-input item-stacked-label">
<span class="input-label">Prijs</span>
<input type="text" placeholder=".-" ng-model="formData.price">
</label>
</div>
<ion-list ng-repeat="user in users">
<ion-checkbox ng-click="la()" ng-model="users[user.Username][user.id][user.voltooid == false]" >
</ion-checkbox>
</ion-list>
<div class="button" ng-click="test()">test</div>
The push code
$scope.formData = {};
$scope.test = function (){
console.log($scope.users);
console.log($scope.formData);
posts.push({
title: $scope.formData.title,
description: $scope.formData.description,
price: $scope.formData.price,
users: {
//dynamic data
}
});
}

Answer 1

I'm gonna give you an example how to retrieve and post dynamically your data.
Here is a factory to sync your data with a controller/ng-model, but you can include it in a controller.
.factory("Items", function($firebaseArray) {
var itemsRef = new Firebase("https://YOUR-FIREBASE/");
return $firebaseArray(itemsRef);
})
In your controller you retrieve your data in a scope
$scope.items = Items;
Then use the function of angularfire call $save that will update your data into your firebase.
$scope.la = function(){
$scope.items.$save($scope.users[user.name][check]);
}
Finally you can do something like that to retrieve and update your data
<ion-checkbox ng-click="la()" ng-model="users[user.name][check]">