There is a small bug when a parameter is in the path and under some scopes.

PUT /articles/:id
{
  "data": {
    "type": "articles",
    "id": "1",
    "attributes": {
      "title": "To TDD or Not"
    }
  }
}

It wasn't possible to set the internal id because it was checked the presence in the path.

I've changed to check in the path the presence of the full name (with the scope), since the id in the path won't have any scope the following will work:

parameter :id, 'path id', required: true
parameter :id, 'data id', scope: :data, required: true
let(:id) { 1 }
let(:data_id) { 1 }

I've also improved a bit the readme about scopes