text: -- KV triples table for attaching extra info (filename, tag, etc) to photos
  CREATE TABLE photo_attrs (
    photo_id INTEGER NOT NULL REFERENCES photos
    , key VARCHAR(30) NOT NULL
    , value VARCHAR(100) NOT NULL
    , updated_at TIMESTAMP NOT NULL DEFAULT NOW()
    , PRIMARY KEY (photo_id, key)
  );
  
  -- forgot this when creating the photos table...
  SELECT diesel_manage_updated_at('photos');
  SELECT diesel_manage_updated_at('photo_attrs');
  