redirect course and script overview pages to add the teacher's most recent section_id

[davidsbailey]

Background

line item from spec: https://docs.google.com/document/d/17X2bEVK4YO4gymmVEzAnDYCYTjE5xHQTlDSAZbEprTo/edit#bookmark=id.ljdodx5zi2wn

The idea is to always show a selected section on the course and script overview pages when possible.

Description

If a request from a teacher with sections is made for a course or script overview page without a section_id in the url, perform a redirect which keeps the same url path but replaces the query string with a ?section_id= referring to the id of their most recently created section.

Caveats

In theory if we had other url params, this solution would not be great because we would clobber them. However the only other url params I am aware of on these paths at this time are the ones developers use to enable/disable experiments, so I'm inclined to say YAGNI and deal with preserving the query strong if and when it becomes necessary. If there's a simple way to do this that I'm missing, I don't mind adding it now though.

There are other places, such as script levels, where a teacher might have other url params, such as when they are viewing the level as one of their students. We do not plan to add a default section id in that situation, so we don't have to worry about this solution being generalized to that case.

[islemaster]

🎉 Great, simple solution.