title: forloop.index as a condition in an if-statement in shopify
body: <p><strong>I'm trying to do something very simple.</strong> I wrote:</p>
  
  <pre><code>{% for product in collection.products %}
     {{ if forloop.index = 1 }}
          Hello World!
     {{ endif }}
  {% endfor %}
  </code></pre>
  
  <p><strong>Problem:</strong>
  "Hello World!" appears in every iteration.
  What is wrong here?</p>