CREATE TABLE follows (
    id BIGSERIAL PRIMARY KEY,
    iri VARCHAR,
    follower_id BIGINT REFERENCES accounts (id) ON DELETE CASCADE,
    followee_id BIGINT REFERENCES accounts (id) ON DELETE CASCADE,
    created_at TIMESTAMP NOT NULL DEFAULT now()
);

CREATE UNIQUE INDEX index_follows_on_iri ON follows(iri);
CREATE UNIQUE INDEX index_follows_on_follower_id_and_followee_id ON follows (follower_id, followee_id);