title: Entity Framework Attach not updating collection changes
body: <p>When updating the Viewers collection with a reference to a User with the Id correctly set the DB is not updated with this new reference. All other fields are updated but the collections are not updated.</p>
  
  <pre><code>var entity = new Event
  {
      Id = model.Id,
      Name = model.Name,
      Date = model.Date,
      Location = model.Location,
      EBroadcasters = model.Broadcasters?.Select(b =&gt; new User
      {
          Id = b.Id,
          SkypeId = b.SkypeId,
          Name = b.Name,
          ServiceUrl = b.ServiceUrl
      }).ToList(),
      EViewers = model.Viewers?.Select(v =&gt; new User
      {
          Id = v.Id,
          SkypeId = v.SkypeId,
          Name = v.Name,
          ServiceUrl = v.ServiceUrl
      }).ToList()
  };
  
  _ssRepository.Events.Attach(entity);
  _ssRepository.Entry(entity).State = EntityState.Modified;
  
  // Don't think I need to do this stuff but tried everything to get it to update!!!
  foreach (var b in entity.EBroadcasters)
  {
      _ssRepository.Users.Attach(b);
      _ssRepository.Entry(b).State = EntityState.Modified;
  }
  
  foreach (var v in entity.EViewers)
  {
      _ssRepository.Users.Attach(b);
      _ssRepository.Entry(v).State = EntityState.Modified;
  }
  
  _ssRepository.SaveChanges();
  </code></pre>
  
  <p>Any help would be greatly appreciated!</p>
  
  <p>Gerard</p>