nkf has been extracted as a stdgem since Ruby 3.4

Author: amatsuda

Gemfile

@@ -2,6 +2,8 @@ source "https://rubygems.org"
 
 ruby file: '.ruby-version'
 
+gem 'nkf'
+
 # Bundle edge Rails instead: gem "rails", github: "rails/rails", branch: "main"
 gem "rails", "~> 8.0.0"
 

Gemfile.lock

@@ -167,6 +167,7 @@ GEM
     net-smtp (0.5.1)
       net-protocol
     nio4r (2.7.4)
+    nkf (0.2.0)
     nokogiri (1.18.10-aarch64-linux-gnu)
       racc (~> 1.4)
     nokogiri (1.18.10-aarch64-linux-musl)
@@ -343,6 +344,7 @@ DEPENDENCIES
   capybara
   debug
   importmap-rails
+  nkf
   pg
   puma (>= 5.0)
   rails (~> 8.0.0)