dumping a database in review apps

app.json

{
  "name": "some_app_name",
  "scripts": {
    "postdeploy": "[ \"$RAILS_ENV\" != \"TEST\" ] && pg_dump $PRODUCTION_DATABASE_URL | psql $DATABASE_URL && bundle exec rake db:migrate"
  },
  "env": {
    "PRODUCTION_DATABASE_URL": { "required": true },
    "SOME_VAR": { "required": true },
    "RELEASE_STAGE": "review",
  },
  "formation": {
    "web": {
      "quantity": 1
    }
  },
  "addons": [
    "heroku-postgresql",
    "heroku-redis",
    "whatever-add-on",
  ],
  "buildpacks": [
    {
      "url": "heroku/ruby"
    }
  ],
  "environments": {
    "test": {
      "env": {
        "BASE_URL": "http://localhost:3000"
      },
      "scripts": {
        "test": "bundle exec rake spec"
      }
    }
  }
}