Python express authentication using twitter, google, github needs to be fixed with pythonexpress.org token

[gnurenga]

Social network login is getting failed, seems there is a problem in oath token generated using pythonexpress.in.

[Hemanth211]

We tried with below changes and we are able to log in using github OAuth
1. Configured GitHub OAuth(refer screenshot)

   2. Added GitHub config in settings/common.py(refer the diff of the file)

Please find the pull request for the issue #456