title: Set volume size for postgresql service in docker compose
body: <p>I have the following fragment of my yaml file.</p>
  
  <pre><code>version: '3'
  
  services:
    db:
      image: dockerized_db
      build: ./DB
      volumes:
        - pgdata:/var/lib/postgresql/data
      ports:
      - 5432:5432
  
  volumes:
    pgdata:
  </code></pre>
  
  <p>How can I define size of my volume in docker-compose file for that volume used by db container?</p>