fix(ci): Add test workflow

.github/workflows/tests.yml

@@ -0,0 +1,27 @@
+on:
+  workflow_dispatch:
+  pull_request:
+    branches:
+      - main
+
+name: tests
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    name: Ruby ${{ matrix.ruby }}
+    strategy:
+      matrix:
+        ruby: [2.6, 2.7]
+    steps:
+      - name: Checkout Repository
+        uses: actions/checkout@v4
+
+      - name: Set Up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+
+      - name: Run Tests
+        run: bundle exec rake