This Dockerfile builds a lightweight linux image based on Alpine Linux (5MB to start) with just the run-time tools needed to ruby a Ruby project/worker.
It includes postgres support as a library (i.e. not the Postgres server, but just library code to compile against)
It is currently customized to projects I am working on, so it may not have all the necessary libraries.
NOTE: This is for running. For building a Ruby project in a docker image use: ifpironimages/ruby-build
RUN apk update && apk upgrade
RUN apk add curl libxslt libpq
RUN apk add ruby ruby-bigdecimal ruby-io-console ruby-bundler
RUN gem install --no-ri --no-rdoc bundler
RUN rm -rf /var/cache/apk/*