Setup GitHub Actions

.github/workflows/ci.yml

@@ -0,0 +1,33 @@
+---
+name: Test
+on: [push]
+
+jobs:
+  ruby:
+    name: Ruby ${{ matrix.ruby }}
+    timeout-minutes: 5
+    strategy:
+      fail-fast: false
+      matrix:
+        os: ["ubuntu-latest"]
+        ruby: 
+          - "ruby-head"
+          - "3.1"
+          - "3.0"
+          - "2.7"
+          - "2.6"
+          - "2.5"
+          - "2.4"
+          - "2.3"
+          - "2.2"
+    runs-on: ${{ matrix.os }}
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v2
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+      - name: Test
+        run: bundle exec rake