Populate mentor mailinglist with this year's mentors rather than last year's

Ghost User
2017-12-10T21:29:10+01:00

In !545, a list for mentors is created. However, it's populated with last year's set of mentors. Perhaps converting an offset datetime to a lecture year (e.g. +9 months, to transition on January 1st rather than September 1st?) would be an easy solution.

As of writing, this is an unreleased feature, so it's not a bug in production right now.