title: Django staticfiles not found on Heroku (with whitenoise)
body: <p>This question seems to be asked several time but I can not fix it. </p>
  
  <p>I deployed a django app on production with <code>DEBUG = False</code>. I set my <code>allowed_host</code>. 
  I used <code>{% load static from staticfiles %}</code> to load static files. I exactly write the settings sugested by Heroku doc : </p>
  
  <pre><code>BASE_DIR = os.path.dirname(os.path.dirname(__file__))
  PROJECT_ROOT = os.path.dirname(os.path.abspath(__file__))
  
  STATIC_ROOT = os.path.join(PROJECT_ROOT, 'staticfiles')
  STATIC_URL = '/static/'
  
  STATICFILES_DIRS = (
      os.path.join(PROJECT_ROOT, 'static'),
  )
  
  STATICFILES_STORAGE = 'whitenoise.django.GzipManifestStaticFilesStorage'
  </code></pre>
  
  <p>BUT I got an error 500. And got this traceback (by mail)</p>
  
  <pre><code>...
  `cache_name = self.clean_name(self.hashed_name(name))
   File "/app/.heroku/python/lib/python3.5/site-    packages/django/contrib/staticfiles/storage.py", line 94, in hashed_name (clean_name, self))
  ...
  ValueError: The file ‘app/css/font.css’ could not be found with &lt;whitenoise.django.GzipManifestStaticFilesStorage object at 0x7febf600a7f0&gt;.`
  </code></pre>
  
  <p>When I run <code>heroku run python manage.py collectstatic --noinput</code> 
  All seems ok :</p>
  
  <p><code>276 static files copied to '/app/annuaire/staticfiles', 276 post-processed.</code></p>
  
  <p>Does anyone have an idea to help me, please ?</p>
  
  <p>Thanks</p>
  
  <p>EDIT : </p>
  
  <pre><code>annuaire
  |-- /annuaire
  |-- -- /settings.py
  |-- /app
  |-- -- /static/...`
  </code></pre>
  
  <p>wsgi.py</p>
  
  <pre><code>from django.core.wsgi import get_wsgi_application
  from whitenoise.django import DjangoWhiteNoise
  
  
  application = get_wsgi_application()
  application = DjangoWhiteNoise(application)
  </code></pre>