docs: update Container-README.md with Docker build and run instructio…

…ns for rust-backend

docs/runbooks/Container-README.md

@@ -81,13 +81,43 @@ Before you begin, ensure you have the following installed:
          POSTGRES_DB: ${POSTGRES_DB}
          POSTGRES_HOST: ${POSTGRES_HOST}
        ports:
-         - "${WEB_PORT}:8080"
+         - "${WEB_PORT}:4000"
        depends_on:
          - postgres
    ```
 
 ## Building and Running the Application
 
+### **1. Building the rust-backend image**
+
+To build the Docker image for the Rust application, run the following command:
+  
+  ```bash
+  docker buildx build --platform linux/amd64,linux/arm64 -t rust-backend . 
+  ```
+
+- this will build the image for both amd64 and arm64 architectures or you can choose to build for a specific architecture by specifying the `--platform` flag.
+- the image will be tagged as `rust-backend` and will be used in the `docker-compose.yaml` file.
+
+### **2. Running the Rust Backend Application**
+
+  **Interactive Shell Access to Functions:** When you start the container the default behavior is to enter an interactive session, both the binaries and each of the functions from rebuild_db.sh are immediately available:
+
+  ```bash
+  docker run -it rns-backend:latest
+  ```
+
+- Inside the container shell, you can directly call any function from `rebuild_db.sh` directly by name:
+- You can also run any of the binaries or functions from `rebuild_db.sh` directly by name as arguments to the `docker run` command:
+
+```bash
+docker run -it rns-backend:latest seed_db
+```
+
+## Building and Running the Entire Application
+
+To build and run the entire application, including the Rust backend and PostgreSQL database, follow these steps:
+
 ### **Step 1: Build the Docker images**
 
 From the project root, run the following command to build the Docker images for both the Rust application and PostgreSQL (if running locally).