Arrange divs on new row every third time - php

Question

I have this most annoying problem; I'm trying to arrange three divs on a row, and then new row, and another three divs and so on, like this:
<div class="container">
<div class="row">
<div class="col-sm-1">1</div>
<div class="col-sm-1">2</div>
<div class="col-sm-1">3</div>
</div>
<div class="row">
<div class="col-sm-1">4</div>
<div class="col-sm-1">5</div>
<div class="col-sm-1">6</div>
</div>
</div>
As for this accepted answer,
There is one catch: 0 % 3 is equal to 0. This could result in
unexpected results if your counter starts at 0.
So how would i implement this into this code:
<div class="col-md-8">
<?php
foreach($this->movies->movie_data as $key => $movie){
$string = file_get_contents("http://example.com/?t=" . urlencode($movie->movie_titel). "&y=&plot=short&r=json");
$result = json_decode($string);
if($result->Response == 'True'){
?>
<div class="col-sm-4">
<?php if($result->Poster == 'N/A') : ?>
<a href="<?php echo Config::get('URL')?>ladybug/day/<?php echo $this->city ?>/<?php echo $movie->movie_id ?>">
<img src="<?php echo Config::get('URL')?>/images/na.png" class="img-responsive img-thumbnail"></a>
<?php else: ?>
<a href="<?php echo Config::get('URL')?>ladybug/day/<?php echo $this->city ?>/<?php echo $movie->movie_id ?>">
<img src="<?php echo $result->Poster; ?>" class="img-responsive img-thumbnail"></a>
<?php endif; ?>
<div><b><?php echo $result->Title; ?></b></div>
<div><i><?php // echo $result->Plot; ?></i></div>
</div>
<?php }else{ ?>
<div class="col-sm-4">
<a href="<?php echo Config::get('URL')?>ladybug/day/<?php echo $this->city ?>/<?php echo $movie->movie_id ?>">
<img src="<?php echo Config::get('URL')?>/images/na.png" class="img-responsive img-thumbnail"></a>
<div><b><?php echo $movie->movie_titel ?></b></div>
<div class="plot"><i><?php //echo 'N/A' ?></i></div>
</div>
<?php }}} ?
</div>
For some reason, divs is arranged like this:
My question: How do I arrange thumbnails on a new row, every third time?

Answer 1

Found the answer in the other Q... Didn't read, sorry about that.
<?php }
if (($key + 1) % 3 == 0) { ?>
</div>
<?php }
}} ?>