v0.5.0

Changed

• Breaking: admin.Seeder is a mechanism over named sets: States() []string lists the
  names it declares and Seed(ctx, state) applies one. A set is the data a deployment or a
  scenario starts from, declared by the consumer, applied idempotently.
• Breaking: admin.Options.Seed is a state name, the set that applies at every startup once
  the schema is current; empty applies none. A name without a Seeder panics; a name the seeder
  does not declare fails startup with ErrUnknownState.
• Breaking: admin.Service.Seed takes a state name; empty applies the configured set.
  ErrSeedDisabled now means no seeder, or no set named or configured.

Added

• admin.Service.Reset: the transition to a named state. It reverts every applied migration,
  applies the whole set, and seeds the state's set, each through the function the verbs run,
  and returns a Transition with the state, the refreshed Status, and the rows seeded. It
  is destructive, in the class of Down and Force.
• admin.Service.States lists the seeder's declared names; admin.ErrUnknownState classifies
  an undeclared name, refused before any I/O.