Duplicate key migration error - timestamp should not be primary key

[simontabor]

When trying to apply migrations (using default config of pending: true, method: 'all') and there's more than one migration pending, I'm getting a duplicate key error...

duplicate key value violates unique constraint "migrations_pkey" (coming from https://github.com/programble/careen/blob/master/lib/runner.ts#L74)

The schema for the migrations table needs changing - timestamps should never be used as a primary key like this. Whilst in all mode, it's trying to insert multiple rows with the exact same ID.

timestamp can be an indexed column, but not unique. Alternatively a new column of id could be added as a serial primary key, but that seems unnecessary.

Changing the method to each works around the problem for now.