Add rails 8 to CI (#38)

Author: jho406

.github/workflows/build.yml

@@ -13,10 +13,12 @@ jobs:
       fail-fast: false
       matrix:
         ruby: ['3.3', '3.2', '3.1']
-        version: ['70', '71', '72', 'main']
+        version: ['70', '71', '72', '80', 'main']
         exclude:
           - ruby: 3.1
             version: main
+          - ruby: 3.1
+            version: 80
 
     runs-on: 'ubuntu-latest'
 

Gemfile.80

@@ -0,0 +1,7 @@
+source "https://rubygems.org"
+gemspec
+
+gem "rspec"
+gem "byebug"
+gem "rails", "~> 8.0.0"
+gem "standard", group: [:development, :test]