ImportError when running in Docker (compose)

[capncodewash]

Hi there,
When running 'docker compose up' on the 'devel' branch, commit 79d75e7, I get the following traceback:

`Environment:

Request Method: GET
Request URL: http://localhost:8010/

Django Version: 1.11
Python Version: 2.7.9
Installed Applications:
('django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.messages',
'django.contrib.staticfiles',
'testbed.main')
Installed Middleware:
('django.middleware.common.CommonMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware')

Traceback:

File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/exception.py" in inner
41. response = get_response(request)

File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py" in _legacy_get_response
249. response = self._get_response(request)

File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py" in _get_response
187. response = self.process_exception_by_middleware(e, request)

File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py" in _get_response
185. response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "/usr/local/lib/python2.7/dist-packages/django/views/generic/base.py" in view
68. return self.dispatch(request, *args, **kwargs)

File "/usr/local/lib/python2.7/dist-packages/django/views/generic/base.py" in dispatch
88. return handler(request, *args, **kwargs)

File "/app/testbed/main/views.py" in get
55. return super(MainView, self).get(request, payload_hash=payload_hash)

File "/usr/local/lib/python2.7/dist-packages/django/views/generic/base.py" in get
155. context = self.get_context_data(**kwargs)

File "/app/testbed/main/views.py" in get_context_data
59. context['handlers'] = sorted(self.handlers.keys())

File "/app/testbed/main/views.py" in handlers
25. self._handlers = self._get_handlers()

File "/app/testbed/main/views.py" in _get_handlers
40. module = import_module("openformats.formats.{}".format(filename))

File "/usr/lib/python2.7/importlib/init.py" in import_module
37. import(name)

Exception Type: ImportError at /
Exception Value: No module named pycache`

Perhaps there is a missing dependency in the requirements.txt?

Thanks,

Graeme