Add dockerfile

Dockerfile

@@ -0,0 +1,41 @@
+#!/usr/bin/env -S docker build . --tag=decsync-caldav --file
+
+#
+# To run the container, use:
+# 
+# docker run -p 5232:5232 --restart unless-stopped --name decsync-caldav -v <decsync-data-directory>:/decsync-data -it decsync-caldav
+#
+
+
+FROM tomsquest/docker-radicale
+
+# Install dependencies:
+RUN apk add --no-cache libstdc++ libc6-compat
+
+
+# Install the decsync plugin:
+RUN python3 -m pip install --break-system-packages git+https://github.com/mab122/Radicale-DecSync.git@fix/storage_discovery_arguments_mismatch
+
+# TODO: revert the above command to the following, once https://github.com/39aldo39/Radicale-DecSync/pull/34
+# has been merged:
+#
+# RUN python3 -m pip install --break-system-packages radicale_storage_decsync
+
+
+# Create the directory to synchronize:
+RUN mkdir /decsync-data
+
+# Add the decsync plugin configuration:
+RUN echo $' \n\
+[storage] \n\
+type = radicale_storage_decsync \n\
+# filesystem_folder = ~/.var/lib/radicale/collections \n\
+decsync_dir = /decsync-data \n' >> /config/decsync-config
+
+ENV RADICALE_CONFIG="/config/config:/config/decsync-config"
+ENV TAKE_FILE_OWNERSHIP="false"
+
+# The original CMD includes a hardcoded "--config <...>" argument, which makes it ignore the
+# environment variable ("RADICALE_CONFIG"). Thus, we override the CMD:
+CMD ["radicale"]
+