Create a genre_alias table

CREATE TABLE genre_alias ( -- replicate (verbose)
    id                  SERIAL,
    genre               INTEGER NOT NULL, -- references genre.id
    name                VARCHAR NOT NULL,
    locale              TEXT,
    edits_pending       INTEGER NOT NULL DEFAULT 0 CHECK (edits_pending >= 0),
    last_updated        TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
    primary_for_locale  BOOLEAN NOT NULL DEFAULT FALSE,
    CONSTRAINT primary_check CHECK ((locale IS NULL AND primary_for_locale IS FALSE) OR (locale IS NOT NULL))
);