Add basic CI

.github/workflows/ci.yml

@@ -0,0 +1,20 @@
+name: ci
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+  schedule:
+    - cron: "0 0 * * *"
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Terraform
+        uses: hashicorp/setup-terraform@v1
+        with:
+          terraform_wrapper: false
+      - name: Lint Terraform
+        run: |
+          terraform fmt -recursive -check