v0.3.0

• UUID primary keys (auto-detected in Rails, key: Key::Uuid for manual schemas)
• Polymorphic associations (votable post(:hello) sets both _id and _type)
• Custom key strategies (any object with generate(table_name, record_name))
• Custom primary key columns
• Hardcoded IDs
• Multi-file fixture loading via FixtureBot.require

See CHANGELOG for details.