Ruby on Rails on Docker & Alpine Linux

Dockerfile

FROM ruby:2.5-alpine
RUN mkdir /app
WORKDIR /app

RUN \
  set -x \
  && apk upgrade --no-cache \
  && apk add --no-cache --virtual \
  build-dependencies \
  && apk add --no-cache \
  build-base \
  tzdata \
  postgresql-dev \
  libxml2-dev \
  libxslt-dev

COPY Gemfile .
COPY Gemfile.lock .

RUN \
  set -x \
  && gem install rake \
  && bundle config build.nokogiri --use-system-libraries \
  && bundle install \
  && apk del build-dependencies

COPY . .

RUN rm -rf log tmp