rails-api/active_model_serializers — pull request #294 by goshakkk (2013-05-05 08:03:53+00:00)
Title: allow singular embed when serializing association

Having

```ruby
has_one :post, embed: :ids
```

looks especially weird as it's a one-to-one association, hence there is only one id. The following looks better:

```ruby
has_one :post, embed: :id
```