This is a good starting point for getting Python, Django, Postgres running as a service, pytest, black, and pip caching rolling with GitHub Actions.

python-django-postgres-ci.yml

name: CI

on: [push]

jobs:

  test:
    runs-on: ubuntu-latest

    services:
      postgres:
        image: postgres:11
        env:
          POSTGRES_USER: postgres
          POSTGRES_PASSWORD: postgres
          POSTGRES_DB: postgres
        ports: ['5432:5432']
        options: --health-cmd pg_isready --health-interval 10s --health-timeout 5s --health-retries 5

    steps:
      - uses: actions/checkout@v1
        with:
          fetch-depth: 1

      - name: Set up Python 3.7
        uses: actions/setup-python@v1
        with:
          python-version: 3.7

      - uses: actions/cache@v1
        with:
          path: ~/.cache/pip
          key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}
          restore-keys: |
            ${{ runner.os }}-pip-

      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          python -m pip install -r requirements.txt
        if: steps.cache.outputs.cache-hit != 'true'

      - name: Test with black
        run: |
          python -m black --check .

      - name: Test with pytest
        env:
          DATABASE_URL: 'postgres://postgres:postgres@localhost:${{ job.services.postgres.ports[5432] }}/postgres'
        run: |
          python -m pytest

z-docker-publish.yml

name: docker-publish

on:
  push:
    branches:
      - master

jobs:

  docker:
    name: Build and Publish Docker image
    runs-on: ubuntu-latest

    steps:
      - name: Git - Get Sources
        uses: actions/checkout@v1
        with:
          fetch-depth: 1

      - name: Docker - Build
        run: |
          docker build . --file .docker/Dockerfile --tag changeme-web

      - name: Docker - Login
        run: |
          echo ${{ secrets.GITHUB_TOKEN }} | docker login docker.pkg.github.com --username ${{ github.actor }} --password-stdin

      - name: Docker - Tag
        run: |
          docker tag changeme-web docker.pkg.github.com/${{ github.repository }}/changeme-web:latest

      - name: Docker - Push
        run: |
          docker push docker.pkg.github.com/${{ github.repository }}/changeme-web:latest