How do I connect to the host postgres service from the docker container under test

Build Environment Databases
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2

According to the doc it doesn’t come installed, but can be set up with the following code:

dependencies:
  pre:
    - sudo service postgresql stop && sudo apt-get remove -y
      postgresql-9.4 && sudo apt-get update; sudo apt-get install -y
      postgresql-9.3 postgresql-contrib-9.3
    - sudo sed -i "s/\port = 5433/port = 5432/"
      /etc/postgresql/9.3/main/postgresql.conf
    - sudo cp /etc/postgresql/9.4/main/pg_hba.conf
      /etc/postgresql/9.3/main/pg_hba.conf
    - sudo service postgresql restart
    - sudo -u postgres createuser ubuntu -d --superuser
    - createdb circle_test
    - createdb ubuntu

However, I also found this:

Hope either of these help.