Use separate container for the RSS plugin

plugins/rss/Dockerfile

@@ -0,0 +1,16 @@
+FROM ubuntu:16.04
+MAINTAINER Kristian Haugene
+
+# Update packages and install software
+RUN apt-get update \
+    && apt-get -y upgrade \
+    && apt-get -y install curl gcc make ruby2.3-dev \
+    && gem install transmission-rss \
+    && curl -L https://github.com/jwilder/dockerize/releases/download/v0.5.0/dockerize-linux-amd64-v0.5.0.tar.gz | tar -C /usr/local/bin -xzv
+
+ADD . /etc/transmission-rss
+
+ENV TRANSMISSION_DOWNLOAD_DIR=/data/completed \
+    RSS_URL=**None**
+
+CMD ["/etc/transmission-rss/start.sh"]