Udemy Flask SaaS chapter 12 docker build error

gistfile1.txt

chrisg@goetz:~/dev/bsawf/12-creating-a-complete-user-system$ docker-compose up --build
Building website
Step 1 : FROM python:2.7-slim
 ---> faea7032fa5c
Step 2 : MAINTAINER Nick Janetakis <nick.janetakis@gmail.com>
 ---> Using cache
 ---> d1de08ac0499
Step 3 : RUN apt-get update && apt-get install -qq -y   build-essential libpq-dev --no-install-recommends
 ---> Running in 11d71fc38117
Err http://deb.debian.org jessie InRelease
  
Err http://security.debian.org jessie/updates InRelease
  
Err http://deb.debian.org jessie-updates InRelease
  
Err http://security.debian.org jessie/updates Release.gpg
  Could not resolve 'security.debian.org'
Err http://deb.debian.org jessie Release.gpg
  Could not resolve 'deb.debian.org'
Err http://deb.debian.org jessie-updates Release.gpg
  Could not resolve 'deb.debian.org'
Reading package lists...
W: Failed to fetch http://deb.debian.org/debian/dists/jessie/InRelease  

W: Failed to fetch http://deb.debian.org/debian/dists/jessie-updates/InRelease  

W: Failed to fetch http://security.debian.org/dists/jessie/updates/InRelease  

W: Failed to fetch http://deb.debian.org/debian/dists/jessie/Release.gpg  Could not resolve 'deb.debian.org'

W: Failed to fetch http://security.debian.org/dists/jessie/updates/Release.gpg  Could not resolve 'security.debian.org'

W: Failed to fetch http://deb.debian.org/debian/dists/jessie-updates/Release.gpg  Could not resolve 'deb.debian.org'

W: Some index files failed to download. They have been ignored, or old ones used instead.
E: Unable to locate package build-essential
E: Unable to locate package libpq-dev
ERROR: Service 'website' failed to build: The command '/bin/sh -c apt-get update && apt-get install -qq -y   build-essential libpq-dev --no-install-recommends' returned a non-zero code: 100