title: Django: module not found while running in Docker container
body: <p>I'm running a Django project in a Docker container, and I want to add a module (specifically, <a href="https://github.com/korfuri/django-prometheus" rel="nofollow noreferrer">django-prometheus</a>)</p>
  
  <p>I ran: <code>pip install django-prometheus</code> and <code>docker run -p 9090:9090 prom/prometheus</code> successfully, and I made the necessary alterations to my <code>settings.py</code> and <code>urls.py</code> files, as <a href="https://github.com/korfuri/django-prometheus#quickstart" rel="nofollow noreferrer">specified in the README</a></p>
  
  <p>I then rebuilt the project and restarted it, but it is giving me the error <code>ModuleNotFoundError: No module named 'django_prometheus'</code></p>
  
  <p>(full error report:</p>
  
  <pre><code>Traceback (most recent call last):
  api_1           |   File "/usr/local/lib/python3.7/site-packages/gunicorn/arbiter.py", line 583, in spawn_worker
  api_1           |     worker.init_process()
  api_1           |   File "/usr/local/lib/python3.7/site-packages/gunicorn/workers/base.py", line 129, in init_process
  api_1           |     self.load_wsgi()
  api_1           |   File "/usr/local/lib/python3.7/site-packages/gunicorn/workers/base.py", line 138, in load_wsgi
  api_1           |     self.wsgi = self.app.wsgi()
  api_1           |   File "/usr/local/lib/python3.7/site-packages/gunicorn/app/base.py", line 67, in wsgi
  api_1           |     self.callable = self.load()
  api_1           |   File "/usr/local/lib/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 52, in load
  api_1           |     return self.load_wsgiapp()
  api_1           |   File "/usr/local/lib/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 41, in load_wsgiapp
  api_1           |     return util.import_app(self.app_uri)
  api_1           |   File "/usr/local/lib/python3.7/site-packages/gunicorn/util.py", line 350, in import_app
  api_1           |     __import__(module)
  api_1           |   File "/usr/src/app/project/wsgi.py", line 16, in &lt;module&gt;
  api_1           |     application = get_wsgi_application()
  api_1           |   File "/usr/local/lib/python3.7/site-packages/django/core/wsgi.py", line 12, in get_wsgi_application
  api_1           |     django.setup(set_prefix=False)
  api_1           |   File "/usr/local/lib/python3.7/site-packages/django/__init__.py", line 24, in setup
  api_1           |     apps.populate(settings.INSTALLED_APPS)
  api_1           |   File "/usr/local/lib/python3.7/site-packages/django/apps/registry.py", line 89, in populate
  api_1           |     app_config = AppConfig.create(entry)
  api_1           |   File "/usr/local/lib/python3.7/site-packages/django/apps/config.py", line 90, in create
  api_1           |     module = import_module(entry)
  api_1           |   File "/usr/local/lib/python3.7/importlib/__init__.py", line 127, in import_module
  api_1           |     return _bootstrap._gcd_import(name[level:], package, level)
  api_1           | ModuleNotFoundError: No module named 'django_prometheus'
  api_1           | [2019-07-01 12:19:36 +0200] [16] [INFO] Worker exiting (pid: 16)
  </code></pre>
  
  <p>)</p>
  
  <p>Prior to me adding this module the project worked perfectly, what am I missing?</p>