Move Dockerfile to docker directory

docker/app/Dockerfile

@@ -0,0 +1,34 @@
+FROM ruby:2.6.3
+
+RUN curl -sL https://deb.nodesource.com/setup_11.x | bash -
+RUN apt-get update -qq && apt-get install -y nodejs postgresql-client
+RUN npm install -g yarn
+
+# Install Chrome (needed by Capybara). TODO: optional installation, only if needed
+RUN wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb
+RUN dpkg -i /google-chrome-stable_current_amd64.deb; apt-get -fy install
+RUN rm /google-chrome-stable_current_amd64.deb
+
+ENV APP_ROOT /astuto
+RUN mkdir ${APP_ROOT}
+WORKDIR ${APP_ROOT}
+
+# Launch processes in Procfile
+RUN gem install foreman
+
+# Copy Gemfile and install gems
+COPY Gemfile* ${APP_ROOT}/
+RUN bundle install
+
+# Copy package.json and install packages
+COPY package.json yarn.lock ${APP_ROOT}/
+RUN yarn install --check-files
+
+COPY . ${APP_ROOT}
+
+# Add a script to be executed every time the container starts.
+ENTRYPOINT ["./docker-entrypoint.sh"]
+
+EXPOSE 3000
+
+# No default CMD is provided in Dockerfile