Use propshaft instead of sprockets for Rails 8+

Author: Fivell

Gemfile

@@ -4,10 +4,16 @@ gemspec
 default_rails_version = '7.1.0'
 default_activeadmin_version = '3.2.0'
 
-gem 'rails', "~> #{ENV['RAILS'] || default_rails_version}"
+rails_version = ENV['RAILS'] || default_rails_version
+gem 'rails', "~> #{rails_version}"
 gem 'activeadmin', "~> #{ENV['AA'] || default_activeadmin_version}"
-gem 'sprockets-rails'
-gem 'sass-rails'
+
+if Gem::Version.new(rails_version) >= Gem::Version.new('8.0.0')
+  gem 'propshaft'
+else
+  gem 'sprockets-rails'
+  gem 'sass-rails'
+end
 
 group :test do
   gem 'simplecov', require: false