title: Convert list to comma separate values in django template
body: <p>In a view I can do:</p>
  
  <pre><code>l = ['one', 'two', 'three']
  ', '.join(l)
  &gt;&gt;&gt; 'one, two, three'
  </code></pre>
  
  <p>Is there a way to do the same in the template, or do I need to create a custom template filter?</p>