Update the service name for consistency, comment environment variables

docker-compose.yml

@@ -1,17 +1,17 @@
 version: "3.4"
 
 services:
-  seafile-sync:
+  seafile-client:
     image: flowgunso/seafile-client:latest
     volumes:
-      your_shared_volume:/volume
+      - your_shared_volume:/volume
     environment:
-      - SEAF_SERVER=
+      - SEAF_SERVER_URL=    # The URL to your Seafile server.
-      - SEAF_USERNAME=
+      - SEAF_USERNAME=      # Your Seafile username.
-      - SEAF_PASSWORD=
+      - SEAF_PASSWORD=      # Your Seafile password.
-      - SEAF_LIBRARY_UUID=
+      - SEAF_LIBRARY_UUID=  # The Seafile library UUID you want to sync with.
-      - UID=
+      - UID=                # Default is 1000.
-      - GID=
+      - GID=                # Default is 1000.
 
 volumes:
   your_shared_volume: