Currently the oncall schedule script which populates https://wikitech.wikimedia.org/wiki/SRE/Oncall/Schedule fetches the upcoming oncall schedule from $now onwards. This leads to empty (nan) fields when the script is run on Monday, after one or more users shifts has a start date which is in the past.

The script should store recently past oncall shifts (e.g. via sqlite) and show at least a weeks worth of shifts with start dates in the past in the table.