Add rails 8 to matrix test ci and exclude ruby 3.1 drop support for r…

…ails 8

.github/workflows/test.yml

@@ -59,11 +59,14 @@ jobs:
       # have set this up with each database as a separate job, but then we'd be
       # duplicating the matrix configuration three times.
       matrix:
-        gemfile: [ 'rails_6.1', 'rails_7.0', 'rails_7.1', 'rails_7.2' ]
+        gemfile: [ 'rails_6.1', 'rails_7.0', 'rails_7.1', 'rails_7.2', 'rails_8.0.0.beta' ]
 
         # To keep matrix size down, only test highest and lowest rubies.
         # See "Lowest supported ruby version" in CONTRIBUTING.md
         ruby: [ '3.1', '3.3' ]
+        exclude:
+          - gemfile: rails_8.0.0.beta
+            ruby: '3.1'
     steps:
       - name: Checkout source
         uses: actions/checkout@v4