Add detailed Docker deployment guide and instructions

Create a new DOCKER-COMPOSE.md file with comprehensive deployment instructions for TaskFlow using Docker Compose, including environment variable configuration, security best practices, and troubleshooting tips.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: ceced2fc-aa46-458d-ba87-ddd4b7bb1518
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/659922a9-0087-461c-90dd-6d9a58b81d4d/ceced2fc-aa46-458d-ba87-ddd4b7bb1518/ahHWEFX

README.md

@@ -44,7 +44,7 @@ The development version uses in-memory storage by default.
 
 ### Production (Docker)
 
-See [DEPLOYMENT.md](./DEPLOYMENT.md) for comprehensive Docker deployment instructions.
+📦 **[Complete Docker Compose Guide](./DOCKER-COMPOSE.md)** - Step-by-step deployment instructions
 
 **Quick Docker Start:**
 
@@ -53,16 +53,23 @@ See [DEPLOYMENT.md](./DEPLOYMENT.md) for comprehensive Docker deployment instruc
    cp .env.example .env
    ```
 
-2. **Start services:**
+2. **Edit `.env` and set a secure password:**
+   ```env
+   POSTGRES_PASSWORD=your_secure_password_here
+   ```
+
+3. **Start services:**
    ```bash
    docker-compose up -d
    ```
 
-3. **Access application:**
+4. **Access application:**
    ```
    http://localhost:5000
    ```
 
+For detailed instructions including environment variables, security settings, troubleshooting, and database management, see **[DOCKER-COMPOSE.md](./DOCKER-COMPOSE.md)**.
+
 ## Project Structure
 
 ```