Use class instance variable for installing

Author: justin808

lib/tasks/webpacker/install.rake

@@ -4,7 +4,8 @@ bin_path = ENV["BUNDLE_BIN"] || Rails.root.join("bin")
 namespace :webpacker do
   desc "Install Webpacker in this application"
   task install: [:check_node, :check_yarn] do |task|
-    @@webpacker_installing = true
+    Webpacker::Configuration.installing = true
+
     prefix = task.name.split(/#|webpacker:install/).first
 
     if Rails::VERSION::MAJOR >= 5

lib/webpacker/configuration.rb

@@ -3,6 +3,10 @@
 require "active_support/core_ext/hash/indifferent_access"
 
 class Webpacker::Configuration
+  class << self
+    attr_accessor :installing
+  end
+
   attr_reader :root_path, :config_path, :env
 
   def initialize(root_path:, config_path:, env:)
@@ -80,7 +84,7 @@ def load
       end
       config[env].deep_symbolize_keys
     rescue Errno::ENOENT => e
-      if @@webpacker_installing
+      if self.class.installing
         {}
       else
         raise "Webpacker configuration file not found #{config_path}. " \