AngularJS ng model with an array

I am trying to let users choose add text field to a form and currently i have set up my controllers like this

  $scope.campaign = {name:"", question:"",answers:[]};
 var totalAnswers = 2;
var totalAnswerAdded = 0;
var utils = {
    initAnswerFields : function(){
        var answers = angular.element("#answer-fields");
        var input;
        console.log("ADDING");
        while(totalAnswerAdded < totalAnswers){
            $scope.campaign.answers.push({answer:""});
            input = angular.element("<input type='text' data-name='answer-"+totalAnswerAdded+"' data-ng-model='campaign.answers["+totalAnswerAdded+"].answer' />");
            answers.append(input);
            totalAnswerAdded++;
        }


    },
    addAnswerFields : function(){

    }
};
var init = function(){
    utils.initAnswerFields();
    utils.addAnswerFields();
};
init();

It is adding input field as expected but changing answer field is not updating the model value. First of all, is it doable like this and if so what am I doing wrong.

You shouldn't be doing DOM manipulation at all here (especially not in your controller). Angular has ng-repeat to iterate over each item within an array/object. So you should set up your view to react to changes in the model:

<div ng-controller="ctrl">
    <div ng-repeat="answer in campaign.answers">
        <input type="text" data-ng-model="answer.value">
    </div>
</div>

Then in your controller you change the data that the view will represent:

app.controller('ctrl', function ($scope) {
    var totalAnswers = 2;
    var totalAnswerAdded = 0;

    $scope.campaign = {name:"", question:"",answers:[]};

    var utils = {
        initAnswerFields: function() {
            while(totalAnswerAdded < totalAnswers) {
                $scope.campaign.answers.push({value: ''});
                totalAnswerAdded++;
            }
        }
    };

    var init = function() {
        utils.initAnswerFields();
        utils.addAnswerFields();
    };

    init();
});