ALTER TABLE vouches ADD COLUMN source TEXT NOT NULL DEFAULT 'computer.ngp.provenance.vouch';
DROP TRIGGER IF EXISTS trust_vouch_delete;
DROP TRIGGER IF EXISTS trust_vouch_update;
DROP INDEX IF EXISTS trust_dependencies_vouch;
ALTER TABLE trust_dependencies RENAME TO legacy_trust_dependencies;
CREATE TABLE trust_dependencies (
    cache_key TEXT NOT NULL REFERENCES trust_cache(cache_key) ON DELETE CASCADE,
    author TEXT NOT NULL,
    record_key TEXT NOT NULL,
    source TEXT NOT NULL DEFAULT 'computer.ngp.provenance.vouch',
    PRIMARY KEY(cache_key, author, source, record_key)
);
INSERT INTO trust_dependencies(cache_key, author, record_key)
SELECT cache_key, author, record_key FROM legacy_trust_dependencies;
DROP TABLE legacy_trust_dependencies;