Update Ruby to 4.0 and Rails to 8.0

Gemfile

@@ -20,10 +20,10 @@ group :development, :test do
   gem "pry-byebug", "~> 3.10"
   gem "rake", "~> 13.0"
   gem "rack-test", "~> 2.1"
-  gem "rails", "~> 6.1.7"
+  gem "rails", "~> 8.0"
   gem "rspec", "~> 3.13"
-  gem "sqlite3", "~> 1.4"
-  gem "rubocop", "~> 1.22"
+  gem "sqlite3", "~> 2.0"
+  gem "rubocop", "~> 1.60"
   gem "rubocop-rake", "~> 0.7"
   gem "rubocop-rspec", "~> 2.31"
   gem "simplecov", "~> 0.22"