title: Getting permission exception when run docker-compose up with dpage/pgadmin4 image
body: <p>I'm trying to build a ruby rails docker-compose postgreSQL db with pgadmin4, but keep getting permission exception from the container. Even /bin/sh in the container returns the same error.</p>
  
  <p>I'm using Ubuntu 18.04.3 LTS</p>
  
  <p>Full log</p>
  
  <pre><code>db_1            | 
  db_1            | PostgreSQL Database directory appears to contain a database; Skipping initialization
  db_1            | 
  db_1            | LOG:  database system was shut down at 2020-02-05 07:15:13 UTC
  db_1            | LOG:  MultiXact member wraparound protections are now enabled
  db_1            | LOG:  autovacuum launcher started
  db_1            | LOG:  database system is ready to accept connections
  pgadmin_1       | [2020-02-05 07:15:17 +0000] [1] [INFO] Starting gunicorn 19.9.0
  pgadmin_1       | [2020-02-05 07:15:17 +0000] [1] [INFO] Listening at: http://[::]:80 (1)
  pgadmin_1       | [2020-02-05 07:15:17 +0000] [1] [INFO] Using worker: threads
  pgadmin_1       | [2020-02-05 07:15:17 +0000] [13] [INFO] Booting worker with pid: 13
  pgadmin_1       | [2020-02-05 07:15:17 +0000] [13] [ERROR] Exception in worker process
  pgadmin_1       | Traceback (most recent call last):
  pgadmin_1       |   File "/usr/local/lib/python3.7/site-packages/gunicorn/arbiter.py", line 583, in spawn_worker
  pgadmin_1       |     worker.init_process()
  pgadmin_1       |   File "/usr/local/lib/python3.7/site-packages/gunicorn/workers/gthread.py", line 104, in init_process
  pgadmin_1       |     super(ThreadWorker, self).init_process()
  pgadmin_1       |   File "/usr/local/lib/python3.7/site-packages/gunicorn/workers/base.py", line 129, in init_process
  pgadmin_1       |     self.load_wsgi()
  pgadmin_1       |   File "/usr/local/lib/python3.7/site-packages/gunicorn/workers/base.py", line 138, in load_wsgi
  pgadmin_1       |     self.wsgi = self.app.wsgi()
  pgadmin_1       |   File "/usr/local/lib/python3.7/site-packages/gunicorn/app/base.py", line 67, in wsgi
  pgadmin_1       |     self.callable = self.load()
  pgadmin_1       |   File "/usr/local/lib/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 52, in load
  pgadmin_1       |     return self.load_wsgiapp()
  pgadmin_1       |   File "/usr/local/lib/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 41, in load_wsgiapp
  pgadmin_1       |     return util.import_app(self.app_uri)
  pgadmin_1       |   File "/usr/local/lib/python3.7/site-packages/gunicorn/util.py", line 350, in import_app
  pgadmin_1       |     __import__(module)
  pgadmin_1       |   File "/pgadmin4/run_pgadmin.py", line 4, in &lt;module&gt;
  pgadmin_1       |     from pgAdmin4 import app
  pgadmin_1       |   File "/pgadmin4/pgAdmin4.py", line 109, in &lt;module&gt;
  pgadmin_1       |     app = create_app()
  pgadmin_1       |   File "/pgadmin4/pgadmin/__init__.py", line 350, in create_app
  pgadmin_1       |     paths.init_app(app)
  pgadmin_1       |   File "/pgadmin4/pgadmin/utils/paths.py", line 92, in init_app
  pgadmin_1       |     'The user does not have permission to read and write to the '
  pgadmin_1       | Exception: The user does not have permission to read and write to the specified storage directory.
  pgadmin_1       | [2020-02-05 07:15:17 +0000] [13] [INFO] Worker exiting (pid: 13)
  pgadmin_1       | [2020-02-05 07:15:17 +0000] [1] [INFO] Shutting down: Master
  pgadmin_1       | [2020-02-05 07:15:17 +0000] [1] [INFO] Reason: Worker failed to boot.
  ***_pgadmin_1 exited with code 3
  </code></pre>
  
  <p>docker-compose.yml file</p>
  
  <pre><code>version: '3'
  services:
    db:
      image: postgres:9.5
      volumes:
        - postgres:/var/lib/postgresql/data
    pgadmin:
      image: dpage/pgadmin4
      volumes:
        - pgadmin:/var/lib/pgadmin/storage
      ports:
        - '3030:80'
      environment:
        PGADMIN_DEFAULT_EMAIL: 'admin'
        PGADMIN_DEFAULT_PASSWORD: password
      depends_on:
        - db
  volumes:
    postgres:
    pgadmin:
  </code></pre>
  
  <p>(ruby rails services are removed because I don't think it's relevant)</p>
  
  <p>revmoing the volumes in pgadmin container allows me to use /bin/sh in the container, but I can't use any command</p>