Decision records

For anyone who wants to know why the package works the way it does. Each record states one decision, why it was taken and what it rules out.

• ADR 0001 — Store partial dates as ISO 8601 strings in one column
• ADR 0002 — Convert only exact values, and keep a stand-in field for migration history
• ADR 0003 — A range filter takes in the whole of its last period