Comment 7 for bug 1893463

I've pushed a branch to address an issue with the index and upgrade script. From the commit message:

Unique indexes on nullable columns will allow multiple conceptually unique rows if the nullable columns are, in fact, NULL because NULL does not equal itself. This commit uses COALESCE to make sure that the nullable email column in the reporter.schedule table gets a value of the empty string for the purposes of the unique index. The upgrade script now also takes this into account and ignores the email column.

Branch at:

https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/miker/lp1893462_upgrade_script_improvements_signoff