add a parameter to override the lack of 'instructor' role to let a user create a course

[ragesoss]

We encourage people who have taken a Scholars & Scientists course with Wiki Education to then teach in our Wikipedia Student Program. If a user first signed in to the Dashboard via an enrollment link, then the 'onboarding' flow does not let them indicate they are an instructor, and their user permissions will be 0. That means they won't be shown the link to the instructor orientation or the 'create a course' button on the Dashboard home page.

We should add a parameter (such as ?teach) that overrides this to show the instructor version of the landing page, so that fewer users get stuck and need to ask about how to reset their instructor status (via /onboarding) before creating a course.

[STSonyThomas]

Hey can I be assigned this issue?

[ragesoss]

@STSonyThomas we don't usually assign issues, but you are welcome to work on this.