Follow importmap-rails recomendations for engines

Author: marcelolx

config/importmap.rb

@@ -0,0 +1 @@
+pin "@rails/request.js", to: "requestjs.js"

lib/install/requestjs_with_asset_pipeline.rb

@@ -4,4 +4,4 @@
 create_file Rails.root.join("app/javascript/application.js") unless APP_JS_PATH.exist?
 
 say "Import Request.JS in existing #{APP_JS_PATH}"
-append_to_file APP_JS_PATH.join("application.js"), %(import "@rails/requestjs"\n)
+append_to_file APP_JS_PATH.join("application.js"), %(import "@rails/request.js"\n)

lib/requestjs/engine.rb

@@ -6,12 +6,8 @@ class Engine < ::Rails::Engine
       end
     end
 
-    initializer "requestjs.importmap" do
-      if Rails.application.respond_to?(:importmap)
-        Rails.application.importmap.draw do
-          pin "@rails/requestjs", to: "requestjs.js"
-        end
-      end
+    initializer "requestjs.importmap", before: "importmap" do |app|
+      app.config.importmap.paths << Engine.root.join("config/importmap.rb")
     end
   end
 end