title: Magento: Create custom attribute, set default attribute set
body: <p>just one simple but head-scratching question.</p>
  
  <p>I create a attribute, set it to Drop-Down behavior (in Admin-Store, to be seen as a Drop-Down Attribute)
  it is creating quiet smooth, but didn't set the attribute_set.</p>
  
  <p>In short:</p>
  
  <p>is-state:
  my attribute --> not linked to a attribute set</p>
  
  <p>to-state:
  my attribute --> linked to default attribute set</p>