adding github actions

.github/workflows/ci.yml

@@ -0,0 +1,25 @@
+name: ci
+
+on:
+  - push
+
+jobs:
+  docker:
+    if: ${{ github.ref == 'refs/heads/main' }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+
+      - name: Build and push
+        uses: docker/build-push-action@v2
+        with:
+          push: true
+          tags: ghcr.io/${{ github.repository }}:latest