Ensure all AMS options are passed through.

[drn]

See the following for details:

• https://github.com/rails-api/active_model_serializers/blob/master/docs/general/rendering.md
• https://github.com/rails-api/active_model_serializers/blob/master/docs/general/adapters.md

Should address issue https://github.com/ruby-grape/grape-active_model_serializers/issues/69

[drn]

@dblock - issue creator confirmed that this solves their issue

[drn]

going to close these out