title: Adding attributes to customer entity
body: <p>my current goal is to add a new customer attribute (with <code>int</code> type) which should appear as select with predefined options (loaded from a model with entries editable in backend, which is done).
  I'm struggling with proper use of <code>$installer-&gt;addAttribute()</code> method, especially specifying correct source option. Other problem is the new attribute isn't saved to eav_entity_attribute table</p>
  
  <p>I'm on Magento CE 1.5.1.0</p>