Merge pull request #2327 from alphagov/dockerfile-tlc

Update Dockerfile to reflect it should only run in RAILS_ENV=production

Dockerfile

@@ -2,8 +2,10 @@ FROM ruby:2.7.2
 RUN apt-get update -qq && apt-get upgrade -y && apt-get install -y build-essential nodejs && apt-get clean
 RUN gem install foreman
 
+# This image is only intended to be able to run this app in a production RAILS_ENV
+ENV RAILS_ENV production
+
 ENV GOVUK_APP_NAME static
-ENV RAILS_ENV development
 ENV REDIS_URL redis://redis
 ENV PORT 3013
 
@@ -13,10 +15,12 @@ RUN mkdir $APP_HOME
 WORKDIR $APP_HOME
 ADD .ruby-version $APP_HOME/
 ADD Gemfile* $APP_HOME/
-RUN bundle install
+RUN bundle config set deployment 'true'
+RUN bundle config set without 'development test'
+RUN bundle install --jobs 4
 
 ADD . $APP_HOME
 
-RUN GOVUK_WEBSITE_ROOT=https://www.gov.uk GOVUK_APP_DOMAIN=www.gov.uk RAILS_ENV=production bundle exec rails assets:precompile
+RUN GOVUK_WEBSITE_ROOT=https://www.gov.uk GOVUK_APP_DOMAIN=www.gov.uk bundle exec rails assets:precompile
 
 CMD foreman run web