Documentation needed for valid columns, authorization issues.

[bcipolli]

In the README.md. it should be clearer to users what valid columns are.

Perhaps a link here:
https://developer.atlassian.com/jiradev/jira-platform/jira-architecture/database-schema

But if there are better docs, that'd be great - I'm struggling to use the plugin effectively.

Also a link to resolving authorization issues, including:

• Don't use your email address.
• You may need to set / reset your password in your profile, if you login via Google OAUTH

See:
https://community.atlassian.com/t5/JIRA-questions/JIRA-Rest-API-authentication-always-returns-401-unauthorized/qaq-p/187181