Fix rails 6 deprecation warnings

lib/best_in_place/engine.rb

@@ -1,8 +1,11 @@
 module BestInPlace
   class Engine < Rails::Engine
     initializer 'best_in_place' do
-      ActionView::Base.send(:include, BestInPlace::Helper)
-      ActionController::Base.send(:include, BestInPlace::ControllerExtensions)
+      ActiveSupport.on_load(:action_controller) do
+        ActionView::Base.send(:include, BestInPlace::Helper)
+
+        ActionController::Base.send(:include, BestInPlace::ControllerExtensions)
+      end
     end
   end
 end

lib/best_in_place/railtie.rb

@@ -4,7 +4,7 @@
 module BestInPlace
   class Railtie < ::Rails::Railtie #:nodoc:
     config.after_initialize do
-      BestInPlace::ViewHelpers = ActionView::Base.new({}, {}, "")
+      BestInPlace::ViewHelpers = ActionView::Base.respond_to?(:empty) ? ActionView::Base.empty : ActionView::Base.new
     end
   end
 end