Bitbucket Pipeline: Can't find postgres service

[DW]

I'm having a hard time getting my bitbucket-pipelines.yml to work. It keeps getting stuck on rake db:migrate with the error: PG::ConnectionBad: could not translate host name "db" to address: Name or service not known

I see the service running though, with no errors. I am at a loss why it's not working. Here is my configuration so far:

image: ruby:2.5
clone:
 depth: full
pipelines:
 default:
  - step:
   script:
    - curl -sL https://deb.nodesource.com/setup_8.x | bash -
    - apt-get update
    - apt-get install nodejs -y
    - curl -o- -L https://yarnpkg.com/install.sh | bash -s -- --version 1.5.1
    - export PATH=$HOME/.yarn/bin:$PATH
    - yarn
    - bundle install
    - rake db:migrate
    - rake db:test:prepare
    - rake test
    - git push https://heroku:$HEROKU_API_KEY@git.heroku.com/$HEROKU_APP_NAME.git HEAD
   services:
    - db

definitions:
 services:
  db:
   image: postgres
   environment:
    POSTGRES_DB: app_test

[DW]

Ended up fixing this by making a pipeline specific database.yml file and overwriting the original in the pipeline. In the pipeline specific yml I have it look for postgres on localhost with port 5432.

I thought that the pipeline configuration would work like docker-compose but that is not the case apparently.