Better nested scaffold generator

[koppen]

Generating a scaffold for a resource that is supposed to be nested under another requires a ton of changes after generating a regular scaffold.

We could create a nested_scaffold generator, that took care of this for us, by making a few assumptions.

• Only index, new, and create actions are required to be nested under the parent resource. Edit, update, and destroy all operate on a concrete resource, ie with a given id, so it has no benefit from being nested.

      resources :inventions do
        resources :patent_applications, :only => [:create, :index, :new]
      end
      resources :patent_applications, :except => [:create, :index, :new]
  

• Resources can only be nested one level deep. Having a House resource nested at
  /cities/:city_id/streets/:street/:street_id/houses/:id makes sense, it doesn't provide anything but long urls and url helper names when compared to having it at /houses/:id.