Dokku deploy setup (#1)

* fix: remove config.key from Dockerfile

* refactor: remove redis

* chore: update README

* feat: precompile assets on build Dockerfile

Dockerfile

@@ -1,13 +1,15 @@
 FROM ruby:2.6.3-alpine
 
+ARG RAILS_MASTER_KEY=''
+ENV RAILS_MASTER_KEY ${RAILS_MASTER_KEY}
+
+ENV RAILS_ENV production
 ENV APP_PATH /usr/src/app
 ENV BUNDLE_VERSION 2.1.4
-ENV RAILS_LOG_TO_STDOUT true
-ENV RAILS_ENV production
 
 WORKDIR $APP_PATH
 
-EXPOSE $RAILS_PORT
+EXPOSE 3000
 
 ENV ALPINE_MIRROR "http://dl-cdn.alpinelinux.org/alpine"
 RUN echo "${ALPINE_MIRROR}/v3.11/main/" >> /etc/apk/repositories
@@ -30,17 +32,15 @@ RUN gem install bundler --version "$BUNDLE_VERSION"
 COPY ./Gemfile .
 COPY ./Gemfile.lock .
 
-RUN bundle install --jobs 20 --retry 5
+RUN bundle install --binstubs
 
 COPY ./package.json .
 COPY ./yarn.lock .
 
-RUN yarn
+RUN yarn --production
 
 COPY . .
 
-RUN chmod 600 config/master.key
-
 RUN bundle exec rails assets:precompile
 
-CMD ["bundle", "exec", "rails", "s", "-b", "0.0.0.0"]
+CMD ["bundle", "exec", "rails", "s", "-b", "0.0.0.0"]