fix(dockerfile): explicitly create a volume and set permission for project dir (#471)

Signed-off-by: NKibo Hikari <enra@sayonika.moe>

Dockerfile

@@ -39,9 +39,15 @@ RUN adduser --gecos '' --disabled-password coder && \
 
 USER coder
 # We create first instead of just using WORKDIR as when WORKDIR creates, the user is root.
-RUN mkdir -p /home/coder/project
+RUN mkdir -p /home/coder/project && \
+    chmod g+rw /home/coder/project;
+
 WORKDIR /home/coder/project
 
+# This assures we have a volume mounted even if the user forgot to do bind mount.
+# XXX: Workaround for GH-459 and for OpenShift compatibility.
+VOLUME [ "/home/coder/project" ]
+
 COPY --from=0 /src/packages/server/cli-linux-x64 /usr/local/bin/code-server
 EXPOSE 8443