"poetry config" command does not create path to config.toml in 1.0.0a4

• I am on the latest Poetry version.
• I have searched the issues of this repo and believe that this is not a duplicate.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: Ubuntu 18.04 w/ python3.7 (in docker container)
• Poetry version: 1.0.0a4
• Link of a Gist with the contents of your pyproject.toml file: N/A

Issue

The poetry config command does not auto create the path to the directory in latest preview version:

root@58ef10ebedba:/build# poetry --version
Poetry version 1.0.0a4
root@58ef10ebedba:/build# poetry config -vvv settings.virtualenvs.in-project true

[FileNotFoundError]
[Errno 2] No such file or directory: '/root/.config/pypoetry/config.toml'

Traceback (most recent call last):
  File "/usr/local/lib/python3.7/dist-packages/clikit/console_application.py", line 131, in run
    status_code = command.handle(parsed_args, io)
  File "/usr/local/lib/python3.7/dist-packages/clikit/api/command/command.py", line 112, in handle
    status_code = self._do_handle(args, io)
  File "/usr/local/lib/python3.7/dist-packages/clikit/api/command/command.py", line 160, in _do_handle
    return getattr(handler, handler_method)(args, io, self)
  File "/usr/local/lib/python3.7/dist-packages/cleo/commands/command.py", line 92, in wrap_handle
    return self.handle()
  File "/usr/local/lib/python3.7/dist-packages/poetry/console/commands/config.py", line 152, in handle
    setting_key, unique_config_values[setting_key], values
  File "/usr/local/lib/python3.7/dist-packages/poetry/console/commands/config.py", line 240, in _handle_single_value
    self._settings_config.add_property(key, normalizer(value))
  File "/usr/local/lib/python3.7/dist-packages/poetry/config.py", line 65, in add_property
    self.dump()
  File "/usr/local/lib/python3.7/dist-packages/poetry/config.py", line 101, in dump
    fd = os.open(str(self._file), os.O_WRONLY | os.O_CREAT, mode)

This works fine in latest stable version:

root@4575f7467c4c:/build# poetry --version
Poetry 0.12.16
root@4575f7467c4c:/build# ls /root/.config
ls: cannot access '/root/.config': No such file or directory
root@4575f7467c4c:/build# poetry config settings.virtualenvs.in-project true
root@4575f7467c4c:/build# ls /root/.config
pypoetry
root@4575f7467c4c:/build# ls /root/.config/pypoetry
auth.toml  config.toml
root@4575f7467c4c:/build# cat /root/.config/pypoetry/config.toml
[settings]
[settings.virtualenvs]
in-project = true

[M5oul]

With 1.0.0a4, I just had to create ~/.config/pypoetry folder and the configuration was working. With 1.0.0b1, I have to create the folder + create the file ~/.config/pypoetry/config.toml.

[brycedrennan]

Great!