Add GHA workflow

.github/workflows/ci_test.yml

@@ -0,0 +1,18 @@
+name: CI
+
+on:
+  pull_request:
+  push:
+    branches:
+      - "master"
+
+concurrency:
+  group: ${{ github.ref_name }}-${{ github.workflow }}
+  cancel-in-progress: true
+
+jobs:
+  rubocop:
+    name: Rubocop
+    uses: theforeman/actions/.github/workflows/rubocop.yml@v0
+    with:
+        command: bundle exec rubocop --parallel --format github