docker: update instructions

install/docker/backend/entrypoint.sh

@@ -1,22 +1,17 @@
 #!/bin/sh
 
 ROOT=/root/.hydro
-mkdir -p $ROOT
 
 if [ ! -f "$ROOT/addon.json" ]; then
     echo '["@hydrooj/ui-default"]' > "$ROOT/addon.json"
 fi
 
 if [ ! -f "$ROOT/config.json" ]; then
-    # TODO 变成变量
     echo '{"host": "oj-mongo", "port": "27017", "name": "hydro", "username": "", "password": ""}' > "$ROOT/config.json"
 fi
 
 if [ ! -f "$ROOT/first" ]; then
     echo "for marking use only!" > "$ROOT/first"
-	hydrooj cli system set file.accessKey "$ACCESS_KEY"
-    hydrooj cli system set file.secretKey "$SECRET_KEY"
-    # TODO 变成变量
     hydrooj cli system set file.endPoint http://oj-minio:9000/
 
     hydrooj cli user create systemjudge@systemjudge.local root rootroot