Add gemfile for Rails 8

Author: djmb

.github/workflows/main.yml

@@ -28,7 +28,7 @@ jobs:
       fail-fast: false
       matrix:
         ruby-version: ["3.1", "3.2", "3.3"]
-        gemfile: [ rails_7_2, rails_main ]
+        gemfile: [ rails_7_2, rails_8_0, rails_main ]
         database: [sqlite, postgres, mysql]
         exclude:
           - ruby-version: "3.1"

gemfiles/rails_8_0.gemfile

@@ -0,0 +1,21 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "sqlite3"
+gem "mysql2"
+gem "pg"
+gem "sprockets-rails"
+gem "appraisal"
+gem "railties", branch: "8-0-stable", git: "https://github.com/rails/rails.git"
+
+group :rubocop do
+  gem "rubocop", ">= 1.25.1", require: false
+  gem "rubocop-minitest", require: false
+  gem "rubocop-packaging", require: false
+  gem "rubocop-performance", require: false
+  gem "rubocop-rails", require: false
+  gem "rubocop-md", require: false
+end
+
+gemspec path: "../"