Add Rails 8 to test matrix

Author: tf

.github/workflows/tests.yml

@@ -18,9 +18,12 @@ jobs:
           - gemfiles/rails_6.x_active_admin_2.x.gemfile
           - gemfiles/rails_6.x_active_admin_3.x.gemfile
           - gemfiles/rails_7.x_active_admin_3.x.gemfile
+          - gemfiles/rails_8.x_active_admin_3.x.gemfile
         include:
           - ruby-version: '4.0'
             gemfile: gemfiles/rails_7.x_active_admin_3.x.gemfile
+          - ruby-version: '4.0'
+            gemfile: gemfiles/rails_8.x_active_admin_3.x.gemfile
 
     env:
       BUNDLE_GEMFILE: ${{ matrix.gemfile }}

Appraisals

@@ -27,3 +27,8 @@ appraise 'rails-7.x-active-admin-3.x' do
   gem 'rails', '~> 7.1'
   gem 'activeadmin', '~> 3.0'
 end
+
+appraise 'rails-8.x-active-admin-3.x' do
+  gem 'rails', '~> 8.0'
+  gem 'activeadmin', '~> 3.0'
+end

gemfiles/rails_8.x_active_admin_3.x.gemfile

@@ -0,0 +1,9 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "sass-rails"
+gem "rails", "~> 8.0"
+gem "activeadmin", "~> 3.0"
+
+gemspec path: "../"