diff --git a/gallery.gemspec b/gallery.gemspec
index 419e85b..ce8659a 100644
--- a/gallery.gemspec
+++ b/gallery.gemspec
@@ -6,6 +6,20 @@ require 'json'
 bundle_update_flag = ARGV[0]=='update' || ARGV[0]=='install'
 if bundle_update_flag
   env_pwd = ENV['PWD']
+  begin
+    require ::File.expand_path('app/helpers/bundler_helper.rb',  env_pwd)
+    extend BundlerHelper
+  rescue LoadError
+    def bundler_with_clean_env
+      if block_given?
+        if Bundler.respond_to?(:with_unbundled_env)
+          Bundler.with_unbundled_env(&Proc.new)
+        else
+          Bundler.with_clean_env(&Proc.new)
+        end
+      end
+    end
+  end
   app_path = File.expand_path(__dir__)
   template_path = env_pwd + '/app/templates'
   all_template = Dir.glob(template_path+'/*/')
@@ -40,9 +54,9 @@ if bundle_update_flag
                     copy_h["name"][locale] = copy_h["name"][locale].sub(/\d+/){|ff| last_index.to_s}
                   end
                   widget_info << copy_h
-                  Bundler.with_clean_env{%x[cp -f #{app_path}/modules/gallery/_#{h["filename"]}.html.erb #{folder}modules/gallery/_#{copy_h["filename"]}.html.erb]}
+                  bundler_with_clean_env{%x[cp -f #{app_path}/modules/gallery/_#{h["filename"]}.html.erb #{folder}modules/gallery/_#{copy_h["filename"]}.html.erb]}
                 elsif h["force_cover"] == "true"
-                  Bundler.with_clean_env{%x[cp -f #{app_path}/modules/gallery/_#{h["filename"]}.html.erb #{folder}modules/gallery/_#{widget_info[widget_info_index]["filename"]}.html.erb]}
+                  bundler_with_clean_env{%x[cp -f #{app_path}/modules/gallery/_#{h["filename"]}.html.erb #{folder}modules/gallery/_#{widget_info[widget_info_index]["filename"]}.html.erb]}
                 end
               end
               if update_flag