[rails] Implement pipeline in routes

Rails allows routing to Rack directly for simple responses:
https://guides.rubyonrails.org/routing.html#routing-to-rack-applications

Author: p8

frameworks/rails/app/controllers/benchmark_controller.rb

@@ -18,10 +18,6 @@ class BenchmarkController < ActionController::API
 
   PG_QUERY = 'SELECT id, name, category, price, quantity, active, tags, rating_score, rating_count FROM items WHERE price BETWEEN $1 AND $2 LIMIT $3'.freeze
 
-  def pipeline
-    render plain: 'ok'
-  end
-
   def baseline11
     total = params[:a].to_i + params[:b].to_i
     if request.post?

frameworks/rails/config/routes.rb

@@ -1,5 +1,5 @@
 Rails.application.routes.draw do
-  get  '/pipeline',    to: 'benchmark#pipeline'
+  get  '/pipeline',    to: ->(env) { [204, {}, ['ok']] }
   get  '/baseline11',  to: 'benchmark#baseline11'
   post '/baseline11',  to: 'benchmark#baseline11'
   get  '/baseline2',   to: 'benchmark#baseline2'