Add bundle install step to Dockerfile for dependency management

Author: andrew

Dockerfile

@@ -36,6 +36,8 @@ RUN apk add --update \
 # Copy application code
 COPY . $APP_ROOT
 
+RUN bundle install --jobs 2
+
 # Precompile assets for a production environment.
 # This is done to include assets in production images on Dockerhub.
 RUN SECRET_KEY_BASE_DUMMY=1 RAILS_ENV=production bundle exec rake assets:precompile