docker documentation for config files is no longer valid

The docker installation instructions (https://github.com/solid/node-solid-server#use-docker) have a step:

docker cp solid:/usr/src/app/config.json .

However by default this file doesn't exist, I get an error:

Error: No such container:path: solid:/usr/src/app/config.json

I was able to successfully create a config file using solid init and then copy it

perhaps these instructions need to be updated to cover some recent changes to the docker setup?

從連結的「use-docker」區段中的 Docker 安裝說明開始，將文件記載的 docker cp 步驟與 issue 中描述的行為進行比較。檢查 solid init 如何在 Docker 設定中建立設定檔。當這些說明能在全新安裝上正確產生或找到設定檔時，即表示完成。