ALTER TABLE zones DROP CONSTRAINT zones_district_id_fkey;
ALTER TABLE zones DROP COLUMN district_id;

ALTER TABLE user_zones DROP CONSTRAINT user_zones_district_id_fkey;
ALTER TABLE user_zones DROP COLUMN district_id;

CREATE TABLE "zone_district" (
    "id"                   uuid PRIMARY KEY,
    "zone_id"              INT NOT NULL,
    "district_id"          INT NOT NULL,
    "created_at"           TIMESTAMPTZ NOT NULL DEFAULT(now())
);
ALTER TABLE "zone_district" ADD FOREIGN KEY ("zone_id") REFERENCES "zones" ("id");
ALTER TABLE "zone_district" ADD FOREIGN KEY ("district_id") REFERENCES "districts" ("id");