Code review comment for lp:~julian-edwards/launchpad/ppa-dependency-schema

 * This is highly structured data, which makes me wonder why it's not structured in the database. We agreed that it's ok because:
   * The field is temporary and only being used for migration
   * There are no use cases for analyzing the data.

I'm ok with this to land on the conditions that:
 * there are comments indicating that it's only for OEM migration
 * we add validation code to guarantee that it's clean, in case we want to migrate to structured data later. If the validation code is not in the model, the comments in the interface should warn that there's no model-level validation.
 * we schedule a date to actually delete this column after OEM have migrated.

Also,
 * Please update the comment field to refer to the URL scheme, both in comments.sql and the interface.