Article: SSO / 3rd party accounts

Proposed title: How do I set up 3rd party accounts for my Hypothesis implementation?

From an email exchange with Jon and an potential partner:

What's currently shipping for SSO, and deployed at elifesciences.org, is a mechanism that is described and demonstrated here: https://github.com/hypothesis/publisher-account-test-site

How it works: A partner site:

- Arranges for permission to create Hypothesis accounts, in a designated group
- Implements the mechanism shown in the above repo

The mechanism enables the partner site to automatically provision Hypothesis accounts mapped to its own user identities, and to serve a Hypothesis client that automatically logs in using those mapped accounts.

There are some limitations on the mapped Hypothesis accounts, which we will address going forward:

- The auto-provisioned Hypothesis account exists only in the context of the partner site
- Auto-provisioned Hypothesis users cannot create and participate in private groups
- Auto-provisioned Hypothesis users do not have access to the "activity pages" dashboard

Hope that's helpful.