feat: add Docker support and bot configuration

- Introduced Dockerfile for building the bot application using Go.
- Added .dockerignore to exclude unnecessary files from the Docker context.
- Updated docker-compose.yml to define the bot service and its dependencies, including environment variables for database and Lavalink configuration.
- Modified internal configuration to streamline environment variable handling.

docker-compose.yml

@@ -1,23 +1,22 @@
 version: "3.9"
 
 services:
-  db:
-    image: postgres:16
-    container_name: velox-postgres
+  bot:
+    build: .
+    container_name: velox-bot
     restart: unless-stopped
+    env_file: .env
     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
+      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:
+      db:
+        condition: service_healthy
+    networks:
+      - default
+      - lavalink
 
-volumes:
-  velox_pgdata:
+networks:
+  lavalink:
+    external: true