Concatenate log, don't overwrite

context/Dockerfile

@@ -17,9 +17,8 @@ RUN apt-get update \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*
 
-RUN touch /var/log/s3-purge
-
 COPY s3-purge.sh /usr/local/bin/s3-purge
 COPY crontab /etc/cron.d/s3-purge
 
-CMD ["tail", "-f", "/var/log/s3-purge"]
+RUN touch /var/log/s3-purge
+CMD ["tail", "-F", "/var/log/s3-purge"]

context/crontab

-20 1 * * * root s3-purge > /var/log/s3-purge 2>/dev/null
+20 1 * * * root s3-purge >> /var/log/s3-purge 2>/dev/null