Edit in JSFiddle

function ExampleController($scope){
  $scope.person = {
    name: 'Kalle',
    age: 22,
    happy: true,
    friends: ['Henri', 'Arto', 'Elina', 'Jorma']
  };

  $scope.addFriend = function(){
    $scope.person.friends.push($scope.newFriend);
  }

  $scope.removeFriend = function(index){
    $scope.person.friends.splice(index, 1);
  }
}

<div ng-app>
    <div ng-controller="ExampleController">
      <ul ng-repeat="friend in person.friends">
        <li>{{friend}} <button ng-click="removeFriend($index)">Poista</button></li>
      </ul>
      <input type="text" ng-model="newFriend">
      <button ng-click="addFriend()">Lisää ystävä</button>
    </div>
</div>