Docker build failure due to bundler flags

[hugginsio]

Bug report

The Docker image fails to build using the docker build -t devdocs . command, perhaps due to Bundler flags:

[+] Building 1.5s (9/11)                                                                                                                                    docker:orbstack
 => [internal] load build definition from Dockerfile                                                                                                                   0.0s
 => => transferring dockerfile: 529B                                                                                                                                   0.0s
 => [internal] load metadata for docker.io/library/ruby:3.4.7                                                                                                          1.1s
 => [internal] load .dockerignore                                                                                                                                      0.0s
 => => transferring context: 104B                                                                                                                                      0.0s
 => [1/7] FROM docker.io/library/ruby:3.4.7@sha256:779ca68b84fe3804e27f5b7ea5ab001005c708b7236a798c15b860d71cba9d21                                                    0.0s
 => [internal] load build context                                                                                                                                      0.1s
 => => transferring context: 118.44kB                                                                                                                                  0.1s
 => CACHED [2/7] WORKDIR /devdocs                                                                                                                                      0.0s
 => CACHED [3/7] RUN apt-get update &&     apt-get -y install git nodejs libcurl4 &&     gem install bundler &&     rm -rf /var/lib/apt/lists/*                        0.0s
 => CACHED [4/7] COPY Gemfile Gemfile.lock Rakefile /devdocs/                                                                                                          0.0s
 => ERROR [5/7] RUN bundle install --system &&     rm -rf ~/.gem /root/.bundle/cache /usr/local/bundle/cache                                                           0.3s
------
 > [5/7] RUN bundle install --system &&     rm -rf ~/.gem /root/.bundle/cache /usr/local/bundle/cache:
0.224 The `--system` flag has been removed because it relied on being remembered
0.224 across bundler invocations, which bundler no longer does. Instead please use
0.224 `bundle config set path.system true`, and stop using this flag
------

 1 warning found (use docker --debug to expand):
 - JSONArgsRecommended: JSON arguments recommended for CMD to prevent unintended behavior related to OS signals (line 24)
Dockerfile:14
--------------------
  13 |
  14 | >>> RUN bundle install --system && \
  15 | >>>     rm -rf ~/.gem /root/.bundle/cache /usr/local/bundle/cache
  16 |
--------------------
ERROR: failed to build: failed to solve: process "/bin/sh -c bundle install --system &&     rm -rf ~/.gem /root/.bundle/cache /usr/local/bundle/cache" did not complete successfully: exit code: 15

OS information

macOS Version 26.1 (25B78), Orbstack Version 2.0.5 (19905)

Steps to reproduce

To quote the README:

git clone https://github.com/freeCodeCamp/devdocs.git && cd devdocs
docker build -t devdocs .
docker run --name devdocs -d -p 9292:9292 devdocs

More resources

NA

Possible fix

I will attempt updating the usage of this flag and then open a PR.