update env variables

.env

@@ -1,5 +1,12 @@
+# Token for the bot received from @BotFather
 TG_TOKEN=
+
+# Domain name where the bot is hosted, needed for Telegram callbacks. No leading protocol, it should be accessible via
+# HTTPS
+# Example: domain.com
 HOST_URL=
 
 # Add non-empty value to enable debug
-#DEBUG=True
+# So far it affects only the mode of running bot, in Debug it's run in "polling" mode while in Production
+# it uses "webhook" mode. Thus, HOST_URL is not required for Debug.
+DEBUG=

docker-compose.yaml

@@ -3,10 +3,8 @@ version: '3'
 services:
   tg-bot:
     build: .
-    environment:
-      - TG_TOKEN=${TG_TOKEN}
-      - DEBUG=${DEBUG}
-      - HOST_URL=${HOST_URL}
+    env_file:
+        - .env
     volumes:
       - ./jobs.sqlite:/app/jobs.sqlite
     ports: