Figure out strategy for database migration

[mcritchlow]

Descriptive summary

When we deploy High Five into k8s, we're going to presumably no longer use the current production database (though we should talk about that)

Under that assumption, we will need a plan for migrating data from the current production database to the new database managed in k8s.

Rationale

When we move the application to k8s we want to do so with no interruption or data loss for current users.