<ul>
    <li ng-repeat="choice in choices" class="choices" ng-click="setSelection(choice)">{{choice}}</li>
</ul>

var choiceSelection = {
        isSelected: false,
        userAnswers: [],
        setSelection: function(choice) {
            this.userAnswers.push(choice);
            console.log(this.userAnswers);
        }
    };