feat: update Docker configuration and environment handling

- Added PostgreSQL service to docker-compose.yml with health checks and persistent storage.
- Updated bot service to use environment variable substitution for database connection string.
- Upgraded Go version in Dockerfile to 1.26.1-alpine.
- Modified config loading to ignore missing .env file for better compatibility with Docker.

Dockerfile

@@ -1,5 +1,5 @@
 # Build stage
-FROM golang:1.22-alpine AS builder
+FROM golang:1.26.1-alpine AS builder
 
 WORKDIR /app
 

docker-compose.yml

@@ -1,13 +1,31 @@
 version: "3.9"
 
 services:
+  db:
+    image: postgres:16
+    container_name: velox-postgres
+    restart: unless-stopped
+    environment:
+      POSTGRES_USER: velox
+      POSTGRES_PASSWORD: velox_pwd
+      POSTGRES_DB: velox
+    ports:
+      - "5432:5432"
+    volumes:
+      - velox_pgdata:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U velox -d velox"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
   bot:
     build: .
     container_name: velox-bot
     restart: unless-stopped
     env_file: .env
     environment:
-      DB_HOST: postgres://velox:velox_pwd@db:5432/velox?sslmode=disable
+      DB_HOST: ${DB_HOST:-postgres://velox:velox_pwd@db:5432/velox?sslmode=disable}
       LAVALINK_HOST: ${LAVALINK_HOST:-ws://lavalink:2333}
       LAVALINK_PASSWORD: ${LAVALINK_PASSWORD:-youshallnotpass}
     depends_on:

internal/config/config.go

@@ -18,9 +18,8 @@ type Config struct {
 }
 
 func LoadConfig() (*Config, error) {
-	if err := godotenv.Load(); err != nil {
+	// Load .env if present (e.g. local dev). Ignore if missing (e.g. Docker injects env vars).
-		return nil, err
+	_ = godotenv.Load()
-	}
 
 	token := os.Getenv("BOT_TOKEN")
 	if token == "" {