title: Ember select for belongsTo doesn't update hasMany end
body: <p>I'm trying to change a belongsTo using the built in ember select view. However, when the select box changes only the belongs to attribute is updated, not the hasMany relationship. The following jsbin shows this behaviour <a href="http://jsbin.com/ewosiy/3/edit" rel="nofollow">http://jsbin.com/ewosiy/3/edit</a>.</p>
  
  <p>In this example a person hasMany events and an event belongsTo a person. If I change who the event belongsTo, the event is removed from the original person but never added to the new person.</p>
  
  <p>I could roll my own select-box component but just wondered if the ember select really is not updating both ends of the relationship.</p>
  
  <p>Thanks.</p>