Add missing workflow

Author: kenhys

.github/workflows/ci.yml

@@ -0,0 +1,32 @@
+name: Testing on Ubuntu
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.head_ref || github.sha }}-${{ github.workflow }}
+  cancel-in-progress: true
+
+permissions: read-all
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby:
+          - 3.2
+          - 3.3
+          - 3.4
+    name: Ruby ${{ matrix.ruby }} unit testing on ${{ matrix.os }}
+    steps:
+    - uses: actions/checkout@v4
+    - uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby }}
+    - name: unit testing
+      run: |
+        bundle install --jobs 4 --retry 3
+        bundle exec rake test