added circleci config, copied from cloud-platform-infra (#16)

.circleci/config.yml

@@ -0,0 +1,32 @@
+# based on: https://github.com/terraform-aws-modules/terraform-aws-vpc/blob/master/.circleci/config.yml
+version: 2
+
+terraform: &terraform
+  docker:
+    - image: hashicorp/terraform:light
+  working_directory: /tmp/workspace/terraform
+
+jobs:
+  validate:
+    <<: *terraform
+    steps:
+      - checkout
+      - run:
+          name: change to terraform directory
+          command: cd terraform
+      - run:
+          name: Validate Terraform configurations
+          command: find . -type f -name "*.tf" -exec dirname {} \;|sort -u | while read m; do (terraform validate -check-variables=false "$m" && echo "√ $m") || exit 1 ; done
+      - run:
+          name: Check if Terraform configurations are properly formatted
+          command: tf=$(terraform fmt -write=false -diff); if [[ -n "$tf" ]]; then printf "$tf\n\n\nSome terraform files failed syntax validation, run 'terraform fmt' to fix\n\n"; exit 1; fi
+      - persist_to_workspace:
+          root: .
+          paths: .
+
+workflows:
+  version: 2
+  build:
+    jobs:
+      - validate
+