Fixed model inclusion in models with aliased references

[cdarne]

If an entity has a field with an alias and it references another entity, the latter won't be included in the model's list.

Entity example:

class AliasedThing < Grape::Entity
  expose :something, as: :post, # the field is aliased
  using: Something, # and it references another entity
  documentation: { type: 'Something', desc: 'Reference to something.' }
end

The doc generated for an action using this entity will include the AliasedThing model but not the Something model.

That's because when the models_with_included_presenters method fails to match aliased fields. When it's looking in each models, it tries to match fields from model.exposure and model.documentation. But model.exposure returns the primary name as key, and model.documentation returns the aliased name as key. That's why they don't match.

Here's my proposition for a fix. It's also a refactoring; I think it would be simpler to iterate just model.exposure and check for a :documentation key.

[dblock]

Thanks this is great. Merged via tim-vandecasteele@30e8c92.