URL to RABL template from rails plugin

Question

My controller looks like this:

module Algo
  class GraphsController < ApplicationController
    respond_to :html, :json

    def show
      @graph = Graph.find(params[:id])
      gon.rabl '../../app/views/algo/graphs/show.json.rabl', as: 'graph' # Hmm
      respond_with(@graph)
    end
  end
end

See the gon.rabl statement, which I'm not too happy with.

Again, this is from a Engine controller, currently mounted inside its test/dummy/ directory.

Any tips to how I get clean this up?