add deploy task

Author: Maksim Litvinov

.github/workflows/main.yml

@@ -14,8 +14,8 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
-      - uses: actions/setup-node@v3
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
         with:
           node-version: '20'
           cache: 'npm'
@@ -27,3 +27,29 @@ jobs:
           make setup
           bin/rails assets:precompile
           make test
+
+  deploy:
+    needs: build
+    runs-on: ubuntu-latest
+    if: ${{ github.event_name == 'push' }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: docker/setup-buildx-action@v3
+
+      - name: Log in to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: true
+          cache-from: ghcr.io/${{ github.repository }}:latest
+          cache-to: type=inline
+          tags: ghcr.io/${{ github.repository }}:latest