Deploy to Heroku button is broken

[vergeev]

The deploy fails on the step Run scripts & scale dynos with the following traceback:

Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/__init__.py", line 363, in execute_from_command_line
    utility.execute()
  File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/__init__.py", line 355, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/base.py", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/base.py", line 327, in execute
    self.check()
  File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/base.py", line 359, in check
    include_deployment_checks=include_deployment_checks,
  File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 62, in _run_checks
    issues.extend(super(Command, self)._run_checks(**kwargs))
  File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/base.py", line 346, in _run_checks
    return checks.run_checks(**kwargs)
  File "/app/.heroku/python/lib/python2.7/site-packages/django/core/checks/registry.py", line 81, in run_checks
    new_errors = check(app_configs=app_configs)
  File "/app/.heroku/python/lib/python2.7/site-packages/django/core/checks/urls.py", line 16, in check_url_config
    return check_resolver(resolver)
  File "/app/.heroku/python/lib/python2.7/site-packages/django/core/checks/urls.py", line 26, in check_resolver
    return check_method()
  File "/app/.heroku/python/lib/python2.7/site-packages/django/urls/resolvers.py", line 254, in check
    for pattern in self.url_patterns:
  File "/app/.heroku/python/lib/python2.7/site-packages/django/utils/functional.py", line 35, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/app/.heroku/python/lib/python2.7/site-packages/django/urls/resolvers.py", line 405, in url_patterns
    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
  File "/app/.heroku/python/lib/python2.7/site-packages/django/utils/functional.py", line 35, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/app/.heroku/python/lib/python2.7/site-packages/django/urls/resolvers.py", line 398, in urlconf_module
    return import_module(self.urlconf_name)
  File "/app/.heroku/python/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/app/permabots_demo/urls.py", line 22, in <module>
    url(r'^docs/', include('rest_framework_swagger.urls', namespace="swagger")),
  File "/app/.heroku/python/lib/python2.7/site-packages/django/conf/urls/__init__.py", line 50, in include
    urlconf_module = import_module(urlconf_module)
  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/rest_framework_swagger/urls.py", line 2, in <module>
    from rest_framework_swagger.views import SwaggerResourcesView, SwaggerApiView, SwaggerUIView
  File "/app/.heroku/python/lib/python2.7/site-packages/rest_framework_swagger/views.py", line 8, in <module>
    from django.shortcuts import render_to_response, RequestContext
ImportError: cannot import name RequestContext