Fixes for oauth keys

[Zircoz]

41

These are changes:

• required dotenv in config file
• suitable doc edits

To deploy on heroku:

• change the redirect and origin uri in your Gcloud Oauth key
• add a new env var in heroku in same format as written in run locally

[Zircoz]

PS: I don't want DWOC labels for this PR and issue, please :D