angularjs ng-repeat checkbox

<div class="col-md-3" ng-repeat="user in title.UserList">
      <p class="form-control-static">
            <input type="checkbox" ng-checked="user.Role" ng-model="item.UserId[user.UserId]" ng-true-value="'add_{{user.UserId}}'" ng-false-value="'del_{{user.UserId}}'"/>&nbsp;{{user.UserName}}
      </p>
</div>```