this looks like it does the trick - first time will issue a config procedure (I know we have redundant files in enigma-bbs-pre but that's a price for the enhanced deployment ease)

docker/Dockerfile

@@ -4,20 +4,12 @@ LABEL maintainer="dave@force9.org"
 
 ENV NVM_DIR /root/.nvm
 ENV DEBIAN_FRONTEND noninteractive
-
-# enigma storage mounts
-VOLUME /enigma-bbs/art
-VOLUME /enigma-bbs/config
-VOLUME /enigma-bbs/db
-VOLUME /enigma-bbs/filebase
-VOLUME /enigma-bbs/logs
-VOLUME /enigma-bbs/mods
-VOLUME /mail
-
 COPY . /enigma-bbs
 
-# Do some installing!
-RUN apt-get update && apt-get install -y \
+# Do some installing! (and alot of cleaning up) keeping it in one step for less docker layers
+# - if you need to debug i recommend to break the steps with individual RUNs)
+RUN apt-get update \
+    && apt-get install -y \
     git \
     curl \
     build-essential \
@@ -29,18 +21,35 @@ RUN apt-get update && apt-get install -y \
     lhasa \
     unrar-free \
     p7zip-full \
-  && npm install -g pm2 \
-  && cd /enigma-bbs && npm install --only=production \
-  && apt-get remove build-essential python libssl-dev git curl -y && apt-get autoremove -y \
-  && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/* \
-  && apt-get clean
+    && npm install -g pm2 \
+    &&  cd /enigma-bbs && npm install --only=production \
+    && pm2 start main.js \
+    &&  mkdir -p /enigma-bbs-pre/art \
+    && mkdir /enigma-bbs-pre/mods \
+    && mkdir /enigma-bbs-pre/config \
+    && cp -rp art/* ../enigma-bbs-pre/art/ \
+    && cp -rp mods/* ../enigma-bbs-pre/mods/ \
+    && cp -rp config/* ../enigma-bbs-pre/config/ \
+    && apt-get remove build-essential python libssl-dev git curl -y \
+    && apt-get autoremove -y \
+    && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/* \
+    && apt-get clean
 
 # sexyz
 COPY docker/bin/sexyz /usr/local/bin
 
+# enigma storage mounts
+VOLUME /enigma-bbs/art
+VOLUME /enigma-bbs/config
+VOLUME /enigma-bbs/db
+VOLUME /enigma-bbs/filebase
+VOLUME /enigma-bbs/logs
+VOLUME /enigma-bbs/mods
+VOLUME /mail
+
 # Enigma default port
 EXPOSE 8888
 
 WORKDIR /enigma-bbs
 
-CMD ["pm2-runtime", "main.js"]
+ENTRYPOINT ["/enigma-bbs/docker/bin/docker-entrypoint.sh"]