🔨 Add CI workflow

.github/workflows/ci.yml

@@ -0,0 +1,23 @@
+name: CI
+on: push
+jobs:
+  ci:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out
+        uses: actions/checkout@v2
+
+      - name: Set up Java
+        uses: actions/setup-java@v1
+        with:
+          java-version: 1.8
+
+      - name: Test
+        run: ./gradlew test
+
+      - name: Upload test reports
+        uses: actions/upload-artifact@v1
+        with:
+          name: test-reports
+          path: build/reports/tests
+        if: always()