CREATE TABLE IF NOT EXISTS "contacts" (
    "id" SERIAL PRIMARY KEY,
    "user_id_a" INTEGER REFERENCES users (id) NOT NULL,
    "user_id_b" INTEGER REFERENCES users (id) NOT NULL,
    "a_to_b" BOOLEAN NOT NULL,
    "should_notify" BOOLEAN NOT NULL,
    "accepted" BOOLEAN NOT NULL
);

CREATE UNIQUE INDEX "index_contacts_user_ids" ON "contacts" ("user_id_a", "user_id_b");
CREATE INDEX "index_contacts_user_id_b" ON "contacts" ("user_id_b");