Add build action

.github/workflows/main.yml

@@ -0,0 +1,23 @@
+
+name: CI on Push and Pull Request
+
+on: [push, pull_request]
+
+jobs:
+  Practice:
+    runs-on: macos-latest
+    steps:
+    - uses: actions/checkout@v1
+    - name: Run a one-line script
+      run: echo Hello, world!
+    - name: Run a multi-line script
+      run: |
+        echo Add other actions to build,
+        echo test, and deploy your project.
+    - name: Show what's in the directory
+      run: |
+        ls
+    - name: Show what all is in the parent directory
+      run: |
+        cd ..
+        ls