Add build workflow

.github/workflows/build.yml

@@ -0,0 +1,34 @@
+name: Build and push
+
+on:
+  push:
+    branches:
+      - "main"
+
+jobs:
+  build_and_push:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Build and push
+        uses: docker/build-push-action@v4
+        with:
+          push: true
+          tags: ghcr.io/kkrt-labs/kakacet/backend:latest
+          context: ./backend
+      - name: Build and push
+        uses: docker/build-push-action@v4
+        with:
+          push: true
+          tags: ghcr.io/kkrt-labs/kakacet/frontend:latest
+          context: ./frontend