title: Docker /run/secrets is not mount
body: <p>I'm trying to provide credentials via secrets. I defined them:</p>
  
  <pre><code>$ docker secret ls
  ID                          NAME                  DRIVER              CREATED             UPDATED
  klsvqjji6bqymndpt3gp1n5na   mysql-password                            35 minutes ago      35 minutes ago
  qpxtfsd2qcah35untcma5qb41   mysql-root-password                       34 minutes ago      34 minutes ago
  mee647yty7uzlxnur1cmf7xg4   mysql-user                                35 minutes ago      35 minutes ago
  </code></pre>
  
  <p>... and I used them in <code>docker-compose.yml</code> file:</p>
  
  <pre><code>version: "3.3"
  
  secrets:
    mysql-user:
      external: true
    mysql-password:
      external: true
    mysql-root-password:
      external: true
  
  services:
     db:
      image: mariadb:10.4.5
      secrets:
        - mysql-user
        - mysql-password
        - mysql-root-password
      environment:
        MYSQL_USER: /run/secrets/mysql-user
        MYSQL_PASSWORD: /run/secrets/mysql-password
        MYSQL_ROOT_PASSWORD: /run/secrets/mysql-root-password
  
        MYSQL_DATABASE: db
      command: ls -l /run
  </code></pre>
  
  <p><code>docker-compose up</code> comamnd returns:</p>
  
  <pre><code>db_1  | total 16
  db_1  | drwxrwxrwt 2 root  root  4096 May 15 14:06 lock
  db_1  | drwxr-xr-x 2 root  root  4096 May 15 14:06 mount
  db_1  | drwxrwxrwx 2 mysql mysql 4096 Jun  4 21:20 mysqld
  db_1  | drwxr-xr-x 2 root  root  4096 May 15 21:20 systemd
  db_1  | -rw-rw-r-- 1 root  utmp     0 May 15 14:06 utmp
  db-security-test_db_1 exited with code 0
  </code></pre>
  
  <p>As you can see there is no secrets <code>directory</code>. Why? What did I miss?</p>
  
  <p>Docker version is 19.03.3.</p>
  
  <p>Docker Compose version is 1.14.1.</p>