Create ci.yml

.github/workflows/ci.yml

@@ -0,0 +1,17 @@
+name: Continuous Integration
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  markdown:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install packages
+        run: sudo gem install mdl
+      - name: Lint markdown files
+        run: mdl *.md