Latest docker image failed to start

[skyingdancing]

When started with the latest docker image ,like:
$ docker pull tomohiro/fluentular:latest
$ docker run -d -p 8080:8080 tomohiro/fluentular:latest
The following error occurred：
/root is not writable.
Bundler will use ‘/tmp/bundler20211019-1-5wk8vt1’ as your home directory temporarily. ``bundler: command not found: rackup ``Install missing gem executables with bundle instal

tomohiro/fluentular:1.11.4 is ok。