Correctly identifies most recent migration

PlanMigration incorrectly identifies the most recent migration. The
query uses alphabetic sorting to order the id's. This results in migration
2_Create_Table.sql being returned instead of 10_Alter_Table.sql as the
most recent migration.

Fixes the issue by querying for all migrations and using the Sort
method on byId to correctly sort Id's. This correctly returns
10_Alter_Table.sql as the most recent migration.