$ python manage.py collectstatic --noinput
   Traceback (most recent call last):
     File "manage.py", line 9, in <module>
       execute_from_command_line(sys.argv)
     File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/__init__.py", line 353, in execute_from_command_line
       utility.execute()
     File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/__init__.py", line 327, in execute
       django.setup()
     File "/app/.heroku/python/lib/python2.7/site-packages/django/__init__.py", line 18, in setup
       apps.populate(settings.INSTALLED_APPS)
     File "/app/.heroku/python/lib/python2.7/site-packages/django/apps/registry.py", line 115, in populate
       app_config.ready()
     File "/app/.heroku/python/lib/python2.7/site-packages/django/contrib/admin/apps.py", line 22, in ready
       self.module.autodiscover()
     File "/app/.heroku/python/lib/python2.7/site-packages/django/contrib/admin/__init__.py", line 26, in autodiscover
       autodiscover_modules('admin', register_to=site)
     File "/app/.heroku/python/lib/python2.7/site-packages/django/utils/module_loading.py", line 50, in autodiscover_modules
       import_module('%s.%s' % (app_config.name, module_to_search))
     File "/app/.heroku/python/lib/python2.7/importlib/__init__.py", line 37, in import_module
       __import__(name)
     File "/app/.heroku/python/lib/python2.7/site-packages/registration/admin.py", line 2, in <module>
       from django.contrib.sites.models import RequestSite
   ImportError: cannot import name RequestSite