automated checks on data presence

[anne-urai]

after a session has been created on Alyx, data should appear on the FlatIron server and then on DataJoint (and in the viewers) 24 hours later. currently, this doesn't always go smoothly and experimenters often find this out only during the weekly meeting.

could there be a cronjob that checks if an Alyx session is in the DataJoint database a day after this session was created? ideally, the DJ team and coordinator would be notified of errors first, who can then contact the experimentalist in case of strange data.