adding github workflow to push docker image

.github/workflows/docker.yml

@@ -0,0 +1,29 @@
+name: Publish Docker image
+
+on:
+  push:
+    branches: [c4t]
+
+jobs:
+  push_to_dockerhub:
+    name: Push Docker image to dockerhub
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@v4
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@3
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASS }}
+
+      - name: Build and push Docker images
+        uses: docker/build-push-action@5
+        with:
+          context: .
+          push: true
+          tags: |
+            c4tplatform/camino-messenger-bot:latest
+            c4tplatform/camino-messenger-bot:${GITHUB_SHA}