ALTER TABLE modules
    ADD COLUMN IF NOT EXISTS icon_url TEXT;

CREATE TABLE IF NOT EXISTS module_capstones (
    id BIGSERIAL PRIMARY KEY,
    module_id BIGINT NOT NULL REFERENCES modules(id) ON DELETE CASCADE,
    title VARCHAR(255) NOT NULL,
    description TEXT,
    tips TEXT,
    thumbnail TEXT,
    question_set_id BIGINT NOT NULL REFERENCES question_sets(id) ON DELETE CASCADE,
    display_order INT NOT NULL DEFAULT 0,
    is_active BOOLEAN NOT NULL DEFAULT TRUE,
    created_at TIMESTAMPTZ NOT NULL DEFAULT CURRENT_TIMESTAMP,
    UNIQUE (question_set_id)
);

CREATE INDEX IF NOT EXISTS idx_module_capstones_module_id
    ON module_capstones (module_id);