title: Docker compose build error
body: <p>If I use command docker-compose build, I'll get error that looks like:</p>
  
  <pre><code>ERROR: Validation failed in file './docker-compose.yml', reason(s):
  Service 'php' configuration key 'expose' '0' is invalid: should be of
  the format 'PORT[/PROTOCOL]'
  </code></pre>
  
  <p>I use the last version docker and docker-compose.</p>
  
  <p>My docker-compose.yml has the next code:</p>
  
  <pre><code>application:
      build: code
      volumes:
          - ./symfony:/var/www/symfony
          - ./logs/symfony:/var/www/symfony/app/logs
      tty: true
  db:
      image: mysql
      ports:
          - 3306:3306
      environment:
          MYSQL_ROOT_PASSWORD: root
          MYSQL_DATABASE: symfony
          MYSQL_USER: root
          MYSQL_PASSWORD: root
  php:
      build: php-fpm
      expose:
          - 9000:9000
      volumes_from:
          - application
      links:
          - db
  nginx:
      build: nginx
      ports:
          - 80:80
      links:
          - php
      volumes_from:
          - application
      volumes:
          - ./logs/nginx/:/var/log/nginx
  elk:
      image: willdurand/elk
      ports:
          - 81:80
      volumes:
          - ./elk/logstash:/etc/logstash
          - ./elk/logstash/patterns:/opt/logstash/patterns
      volumes_from:
          - application
          - php
          - nginx
  </code></pre>
  
  <p>I use an ubuntu 14.04
  Could you tell me how is fix it?</p>