<div class="input-group date" id="completion-date-inputgroup">
<input type="text" class="form-control" id="completion-date" name="completion_date" />
       <span class="input-group-addon">
              <span class="glyphicon glyphicon-calendar"></span>
       </span>
</div>
<script type="application/javascript">
                            $(function () {
                                $('#comletion-date-inputgroup').datetimepicker({
                                    locale: 'de'
                                });
                            });
</script>