Merge remote-tracking branch 'origin/release-2019.0'

* origin/release-2019.0:
  Ensure the cache directory has the right ownership
  Ensure the logfiles exist.

Dockerfile

@@ -49,6 +49,9 @@ ENV CHOWN=dtuuser:dtugroup
 
 RUN chown -R ${CHOWN} /getpdf-server 
 
+# Create and chown this directory so that the volume will inherit the permissions
+RUN chown -R ${CHOWN} /cache
+
 USER dtuuser
 
 ENV NVM_DIR=/getpdf-server/nvm