update db schema to included last updated on for each table #40
Description
Related to #39 we want a way to track when data in the database has been updated.
for an "updated_on" column, alembic won't auto-generated data for existing rows. We need to create a migration manually to support adding columns that have a default value.
One suggestion i've seen is that inside the migration, copy the data to a separate table with a new name, then copy it back into the original named table, with the updated column.