Rails: DB スキーマの変更がマージされたら自動的に tbls を実行して main ブランチに push する

tbls.yml

on:
  push:
    branches: [main]
    paths:
      - db/schema.rb
      - .tbls.yml

permissions:
  contents: write

jobs:
  tbls:
    runs-on: ubuntu-latest
    services:
      mysql:
        image: mysql:5.7
        ports:
          - 3306:3306
        env:
          MYSQL_ALLOW_EMPTY_PASSWORD: y
        options: >-
          --health-cmd "mysqladmin ping"
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5
    steps:
      - name: Checkout
        uses: actions/checkout@v2
        with:
          ref: ${{ github.event.pull_request.head.ref }}
      - uses: ruby/setup-ruby@v1
        with:
          ruby-version: 3.1.2
          bundler-cache: true
      - name: Install Bundler
        run: gem install bundler --no-document -v $(grep "BUNDLED WITH" -1 Gemfile.lock | tail -n 1)
      - name: Bundle install
        run: bundle install --path=vendor/bundle --jobs 4 --retry 3
      - name: DB setup
        run: |
          cp config/database.yml.example config/database.yml
          bundle exec rails db:create db:migrate
      - name: Execute tbls
        run: |
          curl -sL https://git.io/use-tbls > use-tbls.tmp && . ./use-tbls.tmp && rm ./use-tbls.tmp
          rm -rf docs/schema
          tbls doc
      - name: Count changed or untracked files
        id: check_diff
        run: |
          git status --porcelain | wc -l
          file_count=$(git status --porcelain | wc -l)
          echo "::set-output name=file_count::$file_count"
      - name: Commit ER graph
        if: ${{ steps.check_diff.outputs.file_count != '0' }}
        run: |
          git config user.name github-actions
          git config user.email github-actions@github.com
          git add docs/schema
          git commit -m "generate ER graphs from actions"
          git push