Add automated tests

.github/workflows/verify.yml

@@ -0,0 +1,64 @@
+name: Verify
+
+# https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#permissions
+permissions:
+  actions: none
+  checks: none
+  contents: none
+  deployments: none
+  id-token: none
+  issues: none
+  discussions: none
+  packages: none
+  pages: none
+  pull-requests: none
+  repository-projects: none
+  security-events: none
+  statuses: none
+
+on:
+  push:
+    branches:
+      - '*'
+  pull_request:
+    branches:
+      - '*'
+
+jobs:
+  test:
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 40
+
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby:
+          - '3.1'
+          - '3.2'
+          - '3.3'
+        os:
+          - ubuntu-20.04
+          - windows-2019
+          - macos-13
+          - ubuntu-latest
+        exclude:
+          - { os: ubuntu-latest, ruby: '2.7' }
+          - { os: ubuntu-latest, ruby: '3.0' }
+
+    env:
+      RAILS_ENV: test
+
+    name: ${{ matrix.os }} - Ruby ${{ matrix.ruby }}
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+
+      - name: rspec
+        run: |
+          bundle exec rspec