Update Action to add CNAME file

.github/workflows/pelican.yml

@@ -9,11 +9,28 @@ on:
 
 jobs:
   build:
-
     runs-on: ubuntu-latest
 
     steps:
     - uses: actions/checkout@v2
-    - uses: bimbimprasetyoafif/pelican-simple@v1
+
+    - name: Build Pelican website
+      uses: bimbimprasetyoafif/pelican-simple@v1
       env:
-        GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
+        GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
+
+    - name: Check-out gh-pages branch
+      uses: actions/checkout@v2
+      with:
+        ref: gh-pages
+        path: gh-pages
+
+    - name: Create CNAME file
+      run: echo "saocarlos.pyladies.com" > ./gh-pages/CNAME
+
+    - name: Add CNAME file to gh-pages branch
+      uses: EndBug/add-and-commit@v9
+      with:
+        message: 'Add CNAME'
+        add: 'CNAME'
+        cwd: 'gh-pages'