Add ability to "fix" future dates via Manage

[tillson]

From the README:

"The app figures out what week it currently is (A/B) from the portergaud.edu calendar. Using a cron task set to run daily, it pulls the official list of events for the day and searches for a reference to the current week (i.e. the string 'A Week' or 'Week A' for A weeks). If unable to find this (due to administrator error), the app defaults to an A week. For future dates, the app uses whether the week is even or odd (which is an A week/B week is set in the code) in an attempt to "guess" the week. In the future, this is something that can be improved as extended breaks (i.e. Spring Break) "throws off" the algorithm and requires manual intervention."

Some way to try to "fix" this when it happens, using a field in the PostgreSQL database would greatly improve future dates and would require less code intervention.