Debian stretch (fixes #2811) (#2865)

* Switch base operating system image to Debian 9 (Stretch).

* Change dependency names

* Omit npm dependency for now

* Install NPM just like https://github.com/Starefossen/docker-ruby-node/

* Add gpg key and define node version

* Simplify use Stretch backports

* Use backported nodejs.

* Confirm apt installation

* Install by setup script from nodejs.org

* Install nodejs package

* Don't use sudo

Dockerfile

@@ -1,9 +1,8 @@
 # Dockerfile # Plots2
 # https://github.com/publiclab/plots2
 
-FROM ruby:2.4.1-jessie
+FROM ruby:2.4.1-stretch
 
-LABEL maintainer="Sebastian Silva <sebastian@fuentelibre.org>"
 LABEL description="This image deploys Plots2."
 
 # Set correct environment variables.
@@ -18,7 +17,8 @@ ENV PHANTOMJS_VERSION 2.1.1
 #    > /etc/apt/sources.list
 
 # Install dependencies
-RUN apt-get update -qq && apt-get install -y bundler libmysqlclient-dev ruby-rmagick libfreeimage3 nodejs-legacy npm wget procps cron make
+RUN curl -sL https://deb.nodesource.com/setup_8.x | bash -
+RUN apt-get update -qq && apt-get install -y build-essential bundler libmariadbclient-dev ruby-rmagick libfreeimage3 wget curl procps cron make nodejs
 RUN wget https://github.com/Medium/phantomjs/releases/download/v$PHANTOMJS_VERSION/phantomjs-$PHANTOMJS_VERSION-linux-x86_64.tar.bz2 -O /tmp/phantomjs-$PHANTOMJS_VERSION-linux-x86_64.tar.bz2; tar -xvf /tmp/phantomjs-$PHANTOMJS_VERSION-linux-x86_64.tar.bz2 -C /opt ; cp /opt/phantomjs-$PHANTOMJS_VERSION-linux-x86_64/bin/* /usr/local/bin/
 RUN npm install -g bower