Add basic proxy for customers dot

app/controllers/customers_dot/proxy_controller.rb

+# frozen_string_literal: true
+
+module CustomersDot
+  class ProxyController < ApplicationController
+    skip_before_action :authenticate_user!
+    skip_before_action :verify_authenticity_token
+
+    BASE_URL = Gitlab::SubscriptionPortal::SUBSCRIPTIONS_URL
+
+    def graphql
+      response = Gitlab::HTTP.post("#{BASE_URL}/graphql",
+        body: request.raw_post,
+        headers: { 'Content-Type' => 'application/json' }
+      )
+
+      render json: response.body, status: response.code
+    end
+  end
+end

config/routes.rb

@@ -284,6 +284,7 @@ Rails.application.routes.draw do
 
   draw :git_http
   draw :api
+  draw :customers_dot
   draw :sidekiq
   draw :help
   draw :google_api

config/routes/customers_dot.rb

+# frozen_string_literal: true
+
+namespace :customers_dot do
+  post 'proxy/graphql' => 'proxy#graphql'
+end