Add a CRUD extension

[dblock]

See https://github.com/dblock/grape-with-roar/blob/765b6fc0c117e70546161ced37da86cc0e18a8d4/api/extensions/crud_extension.rb, a simple CRUD extension that lets you write API crud in a much more elegant way.

create

spline = create Acme::Models::Spline, with: Acme::Api::Presenters::SplinePresenter, from: params[:spline]
present spline, with: Acme::Api::Presenters::SplinePresenter

update

spline = Acme::Models::Spline.find(params[:uuid])
update spline, with: Acme::Api::Presenters::SplinePresenter, from: params[:spline]

delete

spline = Acme::Models::Spline.find(params[:uuid])
delete spline, with: Acme::Api::Presenters::SplinePresenter