<form class="form" role="form" name="subtaskToList" ng-submit="addSubtask()">

    <div class="form-group">
        <label class="sr-only" for="taskTitle">title</label>
        <div class="col-lg-10">
            <input type="text" class="form-control" id="taskTitle" ng-model="subtask.title" placeholder="add subtask...">
        </div>
    </div>

</form>

<form class="form" role="form" name="subtaskToList" ng-submit="addSubtask(subtask)">

    <div class="form-group">
        <label class="sr-only" for="taskTitle">title</label>
        <div class="col-lg-10">
            <input type="text" class="form-control" id="taskTitle" ng-model="subtask.title" placeholder="add subtask...">
        </div>
    </div>

</form>

Clear subtask textbox immediately after submit.
Clear subtask textbox immediately after submit.
