Dockerfile for Ruby on Rails

Dockerfile

FROM ruby:2.2.2

RUN apt-get update && apt-get install -y nodejs npm mysql-client --no-install-recommends && rm -rf /var/lib/apt/lists/*
RUN update-alternatives --install /usr/bin/node node /usr/bin/nodejs 10

RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app

COPY Gemfile /usr/src/app/
COPY Gemfile.lock /usr/src/app/
COPY package.json /usr/src/app/
RUN bundle install -j4
RUN npm install

COPY . /usr/src/app

EXPOSE 3000
CMD ["bundle", "exec", "unicorn", "-p", "3000", "-c", "config/unicorn/docker.rb"]