explain USER

compose-dev.yml

@@ -22,7 +22,7 @@ services:
          - "8084:8084" # local oauth2 server
 
         environment:
-            - USER
+            - USER            # preset enviroment, UID on the host machine, i.e `id -u` 
             - REMARK_URL=http://127.0.0.1:8080
             - SECRET=12345
             - STORE_BOLT_PATH=/srv/var/db
@@ -32,7 +32,7 @@ services:
             - AUTH_DEV=true   # activate local oauth "dev"
             - ADMIN=dev_user  # set admin flag for local ouath2 
         volumes:
-            - ./var:/srv/var
+            - ./var:/srv/var 
             #- ./web:/srv/web # uncomment to map web directory directly. It will propagate local changes to container without redeploy
 
         command: /srv/start.sh