Add Railties 7 support

Ref:
- rails/rails#43058 

Fix activeadmin#7196

.github/workflows/ci.yaml

@@ -81,7 +81,12 @@ jobs:
 
         os: [ubuntu-20.04]
 
-        deps: [rails_52, rails_60, rails_61, rails_61_turbolinks, rails_61_webpacker]
+        deps: [rails_52, rails_60, rails_61, rails_61_turbolinks, rails_61_webpacker, rails_70]
+
+        exclude:
+          - ruby: { name: 2.6, value: 2.6.6 }
+            os: ubuntu-20.04
+            deps: rails_70
 
         include:
           - ruby: { name: 2.5, value: 2.5.8 }

activeadmin.gemspec

@@ -26,6 +26,6 @@ Gem::Specification.new do |s|
   s.add_dependency "inherited_resources", "~> 1.7"
   s.add_dependency "jquery-rails", "~> 4.2"
   s.add_dependency "kaminari", "~> 1.0", ">= 1.2.1"
-  s.add_dependency "railties", ">= 5.2", "< 6.2"
+  s.add_dependency "railties", ">= 5.2", "< 7.1"
   s.add_dependency "ransack", "~> 2.1", ">= 2.1.1"
 end

gemfiles/rails_70/Gemfile

@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+source "https://rubygems.org"
+
+gem 'inherited_resources', github: 'tagliala/inherited_resources', branch: 'feature/railties-7'
+gem 'ransack', github: 'activerecord-hackery/ransack'
+
+group :development, :test do
+  gem "rake"
+  gem "pry" # Easily debug from your console with `binding.pry`
+  gem "pry-byebug", platform: :mri # Step-by-step debugging
+
+  gem "cancancan"
+  gem "pundit"
+  gem "jruby-openssl", platform: :jruby
+
+  gem "draper"
+  gem "devise", github: 'heartcombo/devise'
+
+  gem "rails", "~> 7.0.0.rc1"
+  gem "activerecord-jdbcsqlite3-adapter", platform: :jruby
+
+  gem "sprockets-rails"
+  gem "sassc-rails"
+end
+
+group :test do
+  gem "cuprite"
+  gem "capybara"
+  gem "webrick"
+  gem "db-query-matchers"
+
+  gem "simplecov", require: false # Test coverage generator. Go to /coverage/ after running tests
+  gem "cucumber-rails", require: false
+  gem "cucumber"
+  gem "database_cleaner"
+  gem "jasmine"
+  gem "jasmine-core"
+  gem "launchy"
+  gem "parallel_tests"
+  gem "rails-i18n" # Provides default i18n for many languages
+  gem "rspec-rails"
+  gem "sqlite3", platform: :mri
+end
+
+gemspec path: "../.."