feat: Update docker images (#1472)

Closes #1329 and #1418.

This addresses the point of #1329 but simplifying a bit the changes of #1418 as the points mentioned in #1329 only need to be addressed for the Dockerfile used for publishing the box image, not the ghcr images which are purely for internal testing.

Author: theofidry

.docker/Dockerfile

@@ -3,6 +3,15 @@ FROM php:8.2-cli-alpine
 COPY --from=mlocati/php-extension-installer /usr/bin/install-php-extensions /usr/local/bin/
 RUN install-php-extensions zlib phar sodium tokenizer filter
 
+# Include Composer as it is required for dumping the autoloader when no external Composer bin is provided.
+COPY --from=composer/composer /composer /usr/bin/composer
+
 COPY bin/box.phar /box.phar
 
+# Adjusts PHP settings
+RUN echo "memory_limit=512M" > /usr/local/etc/php/conf.d/memory-limit.ini \
+    && echo "phar.readonly=Off" > /usr/local/etc/php/conf.d/phar-readonly.ini
+
+RUN mkdir -p /local
+WORKDIR /local
 ENTRYPOINT ["/box.phar"]

doc/installation.md

@@ -89,8 +89,17 @@ The official docker image for the project is [`boxproject/box`][docker-image]:
 
 ```shell
 docker pull boxproject/box
+docker run --rm -v $(pwd):/app boxproject/box
 ```
 
+Beware that with the above you may be limited with the Composer binary used. If you need your own
+Composer binary, you will have to create a docker file to add it to the same volume with the right
+permissions.
+
+Box automatically looks up for a Composer binary and the docker image ships one, if you want to use
+your own you may also need to specify it with `--composer-bin`.
+
+
 ## `shivammathur/setup-php` (GitHub Actions)
 
 Box is supported as a [shivammathur/setup-php tool]: