fix: update environment variable handling in Docker Compose files and improve contributing documentation

README.md

@@ -23,9 +23,11 @@ nest-intra/      # Staff-only internal portal (React + Vite)
 ### 1. Backend Setup
 
 ```bash
-cd nest-backend
+# from repository root
 cp .env.example .env
-# Edit .env with your database credentials
+# Edit .env with your credentials
+
+cd nest-backend
 npm install
 npm run db:push        # Initialize database schema
 npm run db:seed        # Populate with sample data
@@ -35,6 +37,7 @@ npm run dev            # Start dev server (http://localhost:3000)
 #### Backend Environment Variables
 
 ```env
+API_HOST_PORT=3001
 DATABASE_URL="postgresql://user:password@localhost:5432/nest_db"
 JWT_SECRET="your-secret-key"
 PORT=3000