lasse@lsx1 ~/prog/coala/coala (git)-[sils/bfix] % docker run -ti -v $(pwd):/app coala/base coala --files="**/*.py" --bears=PEP8Bear --save -V -c /app
[ERROR][15:31:50] An unknown error occurred. This is a bug. We are sorry for the inconvenience. Please contact the developers for assistance. During execution of coala an exception was raised. This should never happen. When asked for, the following information may help investigating:
[INFO][15:31:50] Exception was:
Traceback (most recent call last):

  File "/coala/coalib/coala_main.py", line 74, in run_coala
    arg_list=arg_list)

  File "/coala/coalib/settings/ConfigurationGathering.py", line 363, in gather_configuration
    save_sections(sections)

  File "/coala/coalib/settings/ConfigurationGathering.py", line 85, in save_sections
    str(default_section.get('config', Constants.default_coafile)))

  File "/coala/coalib/output/ConfWriter.py", line 22, in __init__
    self.__file = open(self.__file_name, 'w')

IsADirectoryError: [Errno 21] Is a directory: '/app'
WARNING: <coalib.output.ConfWriter.ConfWriter object at 0x7f7099635518> was not closed. Cleaning up automatically. Note that this cleanup may not work on other interpreters and is nondeterministic.
Exception ignored in: <bound method ClosableObject.__del__ of <coalib.output.ConfWriter.ConfWriter object at 0x7f7099635518>>
Traceback (most recent call last):
  File "/usr/lib/python3.5/site-packages/pyprint/ClosableObject.py", line 47, in __del__
    self.close()
  File "/usr/lib/python3.5/site-packages/pyprint/ClosableObject.py", line 33, in close
    self._close()
  File "/coala/coalib/output/ConfWriter.py", line 38, in _close
    self.__file.close()
AttributeError: 'ConfWriter' object has no attribute '_ConfWriter__file'