Drop user tokens table
Prefer string interpolation to concatenation
Extend cleanup script to cleanup old OAuth tokens
Fix daily cleanup script for rails 5.2 compatibility
Expire old oauth nonces
Standardise on double quoted strings
Remove session cleanup code from cleanup script
Add exit statement to shut rails up.
Make the cleanup script work a chunk at a time so we don't run out of memory when there are lots of sessions.
Replace the old session cleanup daemon with a new script to be run from cron periodically.