updated docker compose file to set db variables at a single source #55

docker-compose.yml

@@ -5,7 +5,10 @@ db:
     - ./volumes/db/var/lib/postgresql/data:/var/lib/postgresql/data
     - /etc/localtime:/etc/localtime:ro
   # uncomment the following to enable backup
-  #environment:
+  environment:
+    - MM_USERNAME=mattermost_user
+    - MM_PASSWORD=mattermost_password
+    - MM_DBNAME=mattermost_db
   #  - AWS_ACCESS_KEY_ID=XXXX
   #  - AWS_SECRET_ACCESS_KEY=XXXX
   #  - WALE_S3_PREFIX=s3://BUCKET_NAME/PATH