Use database dir for docker image

.docker.json

@@ -3,6 +3,6 @@
   "baseURL": "",
   "address": "",
   "log": "stdout",
-  "database": "/database.db",
+  "database": "/var/lib/filebrowser/database.db",
   "root": "/srv"
 }

Dockerfile

@@ -9,6 +9,7 @@ HEALTHCHECK --start-period=2s --interval=5s --timeout=3s \
 VOLUME /srv
 EXPOSE 80
 
+RUN mkdir /var/lib/filebrowser && chmod a+w /var/lib/filebrowser
 COPY .docker.json /.filebrowser.json
 COPY filebrowser /filebrowser