add ability to login to docker registry

README.md

@@ -31,6 +31,9 @@ Robustly deploy your Docker Compose files to Docker Swarm or regular Docker Comp
 | `build_context_path`  | Local path to Docker build context                             | ❌ No     | `build-context`  |
 | `copy_env_file`       | Whether to copy `.env` file to remote host                     | ❌ No     | `false`          |
 | `env_file_path`       | Local path to `.env` file                                      | ❌ No     | `.env`           |
+| `docker_registry`     | Docker registry URL (defaults to Docker Hub if empty)          | ❌ No     | -                |
+| `docker_username`     | Docker registry username                                       | ❌ No     | -                |
+| `docker_password`     | Docker registry password or token                              | ❌ No     | -                |
 
 ---
 
@@ -80,6 +83,22 @@ This action supports two deployment modes:
     env_file_path: ./production.env
 ```
 
+### Deploying with Private Registry Authentication 🔐
+
+```yaml
+- name: Deploy with Private Registry 🔐
+  uses: your-org/deploy-to-docker-action@main
+  with:
+    stack_name: my-private-stack
+    ssh_host: ${{ vars.SSH_HOST }}
+    ssh_user: ${{ secrets.SSH_USER }}
+    ssh_key: ${{ secrets.SSH_KEY }}
+    deploy_file: docker-compose.yml
+    docker_registry: ghcr.io
+    docker_username: ${{ github.actor }}
+    docker_password: ${{ secrets.GITHUB_TOKEN }}
+```
+
 ---
 
 ## 🧑‍💻 How It Works
@@ -88,7 +107,8 @@ This action performs the following steps:
 
 1. 🔑 **Securely creates a temporary SSH key file** for authentication.
 2. 📁 **Creates a secure temporary directory** on the remote host.
-3. 📤 **Copies your processed Docker Compose file** to the remote host.
+3. 🔐 **Optionally performs Docker login** on the remote host if credentials are provided.
+4. 📤 **Copies your processed Docker Compose file** to the remote host.
 4. 📂 **Optionally copies Docker build context** to the remote host.
 5. 📄 **Optionally copies `.env` file** to the remote host.
 6. 🔍 **Validates the Docker Compose file remotely** to ensure correctness.