1292 order fetched comments

Resubmit pull/3439 closed accidentally by during rebase.  Resolves #1292 
Why not using normal styling:

```ruby
      where(
        resource_type: resource_type(resource),
        resource_id: resource_id_cast(resource),
        namespace: namespace.to_s
      ).order('created_at ASC')
```

In my opinion it's much more expressive.