title: Meteor template autorun is not a function when using es6
body: <p>Works</p>
  
  <pre><code>Template.Hello.onRendered(function() {
    this.autorun(() =&gt; {
      console.log('sup');
    });
  });
  </code></pre>
  
  <p>Doesn't work.</p>
  
  <pre><code>Template.Hello.onRendered(() =&gt; {
    this.autorun(() =&gt; {
      console.log('sup');
    });
  });
  </code></pre>
  
  <p>The error is TypeError: _this.autorun is not a function.</p>
  
  <p>Any ideas why using arrow notation gives us this error?</p>