title: Postgres image is not creating database
body: <p>According to <a href="https://hub.docker.com/_/postgres/" rel="noreferrer">these docs</a>, I can specify the name of the database created by the postgres docker image with the env var <code>POSTGRES_DB</code>. I have set it in my docker-compose file, but it isn't being created.</p>
  
  <p>Here's relevant section from the compose file:</p>
  
  <pre><code>pg:
      image: postgres:10
      volumes:
        - db-data:/var/lib/postgresql/data
      environment:
        POSTGRES_DB: user-auth
        POSTGRES_USER: postgres
        POSTGRES_PASSWORD: postgres
  </code></pre>
  
  <p>Here are the logs:</p>
  
  <pre><code>Attaching to userauth_pg_1
  pg_1   | 2018-02-05 18:05:54.803 UTC [1] LOG:  listening on IPv4 address "0.0.0.0", port 5432
  pg_1   | 2018-02-05 18:05:54.803 UTC [1] LOG:  listening on IPv6 address "::", port 5432
  pg_1   | 2018-02-05 18:05:54.806 UTC [1] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
  pg_1   | 2018-02-05 18:05:54.817 UTC [24] LOG:  database system was interrupted; last known up at 2018-02-05 18:03:26 UTC
  pg_1   | 2018-02-05 18:05:54.942 UTC [24] LOG:  database system was not properly shut down; automatic recovery in progress
  pg_1   | 2018-02-05 18:05:54.944 UTC [24] LOG:  redo starts at 0/1633ED0
  pg_1   | 2018-02-05 18:05:54.944 UTC [24] LOG:  invalid record length at 0/1633F08: wanted 24, got 0
  pg_1   | 2018-02-05 18:05:54.944 UTC [24] LOG:  redo done at 0/1633ED0
  pg_1   | 2018-02-05 18:05:54.955 UTC [1] LOG:  database system is ready to accept connections
  pg_1   | 2018-02-05 18:05:59.140 UTC [31] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:06:15.528 UTC [32] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:08:46.120 UTC [33] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:08:46.151 UTC [34] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:14:02.138 UTC [35] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:14:02.926 UTC [36] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:14:04.244 UTC [37] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:14:04.273 UTC [38] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:14:04.602 UTC [39] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:14:04.910 UTC [40] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:14:05.777 UTC [41] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:14:05.823 UTC [42] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:14:05.878 UTC [43] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:14:06.663 UTC [44] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:14:06.716 UTC [45] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:16:32.713 UTC [46] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:47:04.603 UTC [47] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 18:51:34.413 UTC [1] LOG:  received smart shutdown request
  pg_1   | 2018-02-05 18:51:34.417 UTC [1] LOG:  worker process: logical replication launcher (PID 30) exited with exit code 1
  pg_1   | 2018-02-05 18:51:34.419 UTC [25] LOG:  shutting down
  pg_1   | 2018-02-05 18:51:34.434 UTC [1] LOG:  database system is shut down
  pg_1   | 2018-02-05 19:08:42.934 UTC [1] LOG:  listening on IPv4 address "0.0.0.0", port 5432
  pg_1   | 2018-02-05 19:08:42.934 UTC [1] LOG:  listening on IPv6 address "::", port 5432
  pg_1   | 2018-02-05 19:08:42.937 UTC [1] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
  pg_1   | 2018-02-05 19:08:42.951 UTC [25] LOG:  database system was shut down at 2018-02-05 18:51:34 UTC
  pg_1   | 2018-02-05 19:08:42.956 UTC [1] LOG:  database system is ready to accept connections
  pg_1   | 2018-02-05 19:09:04.316 UTC [32] FATAL:  database "user-auth" does not exist
  pg_1   | 2018-02-05 19:09:18.081 UTC [33] FATAL:  database "user-auth" does not exist
  </code></pre>