GitHub token creation/nbinit

[betatim]

When running nbinit check localconfig.yaml for existing token and reuse it.

If there is no token then use something unique in the note for creating the token as we can't create two tokens with the same name.

[betatim]

Alternatively place the token in ~/.abc.config and share it between all courses.

[lwasser]

Note - this is the error i get running nbinit when i already have a token (just for the record)

Traceback (most recent call last):
  File "/Users/leah-su/anaconda3/bin/nbinit", line 11, in <module>
    sys.exit(init())
  File "/Users/leah-su/anaconda3/lib/python3.6/site-packages/grading/__main__.py", line 60, in init
    two_factor_callback=two_factor)
  File "/Users/leah-su/anaconda3/lib/python3.6/site-packages/github3/api.py", line 26, in deprecation_wrapper
    return func(*args, **kwargs)
  File "/Users/leah-su/anaconda3/lib/python3.6/site-packages/github3/api.py", line 59, in authorize
    client_secret)
  File "/Users/leah-su/anaconda3/lib/python3.6/site-packages/github3/github.py", line 462, in authorize
    json = self._json(self._post(url, data=data), 201)
  File "/Users/leah-su/anaconda3/lib/python3.6/site-packages/github3/models.py", line 156, in _json
    raise exceptions.error_for(response)
github3.exceptions.UnprocessableEntity: 422 Validation Failed

[lwasser]

related to this is -- is this authorize() call deprecated? see here please. something odd is going on with the init command that i can't figure out .i seem to have to delete it each time or every so often. could be user error!

As it currently stands in the PR below, i just check for the config file in the template dir. if that contains the token then nbinit doesn't do anything. If not, it will authenticate and create a token.

NOTE - this will still fail if a token exists (i think??) as i believe authorize() makes a new token. I tried to figure out how to get a list of existing tokens and was having some issue with that. there is a check_auth method that i think might do what we want.

I think we want to

1. check to see if a token exists in the file - do nothing if it's there - all good! maybe print a happy message
2. If it's not there
   a. check to see if that token exists in the gh account. if it does, grab the token vals and add to yml
   b. if it's not there run authorize

[betatim]

Good catch with the deprecation. I hadn't noticed this. Take a look at #40

[betatim]

#40 doesn't quite close this issue as we still use a file local to the repository to store the token instead of placing it in ~/.abc.token (or some such). That is for another PR to solve.