Move secrets to .env file, add .env.example, gitignore .env

.env.example

@@ -0,0 +1,6 @@
+BG_BEARER_TOKEN=your_token_here
+BG_EVENT_ID=1
+BG_RANKING=stableford_gross
+POLL_INTERVAL_MS=10000
+STALE_THRESHOLD_MS=60000
+PORT=3737

.gitignore

@@ -1,2 +1,3 @@
 node_modules/
 *.log
+.env

docker-compose.yml

@@ -7,17 +7,12 @@ services:
       - ./:/app
     command: sh -c "npm install --silent && node server.js"
     ports:
-      - "3737:3737"
-    environment:
-      BG_BEARER_TOKEN: "bg_live_k_K1zO7Jh-fMkRttp8.uoD4OzE3L_SrLXu0tTsS_4nDdL8DkhzRV6eOSXSkivY"
-      BG_EVENT_ID: "1"
-      BG_RANKING: "stableford_gross"
-      POLL_INTERVAL_MS: "10000"
-      STALE_THRESHOLD_MS: "60000"
-      PORT: "3737"
+      - "${PORT:-3737}:${PORT:-3737}"
+    env_file:
+      - .env
     restart: unless-stopped
     healthcheck:
-      test: ["CMD", "wget", "-qO-", "http://localhost:3737/ping"]
+      test: ["CMD", "wget", "-qO-", "http://localhost:${PORT:-3737}/ping"]
       interval: 15s
       timeout: 5s
       retries: 3