Dockerfile needed a update

[leonsgithub]

Hi Thanks for this example. I had to made some changes to the Dockerfile that i'd like to share btw the comment section here errors https://nrempel.com/guides/docker-development-environment/

add the -y switch

RUN apt-get install -y yarn

RUN yarn install

add the modules

RUN yarn add simple-cron amqplib express pg redis