CREATE TABLE "participation" (
  "id" serial NOT NULL,
  PRIMARY KEY ("id"),
  "user_id" integer NOT NULL,
  "event_id" integer NOT NULL,
  "invited_by_user_id" integer NULL,
  "created_at" date NOT NULL,
  "updated_at" date NOT NULL
);

ALTER TABLE "participation"
ADD FOREIGN KEY ("event_id") REFERENCES "event" ("id") ON DELETE CASCADE ON UPDATE CASCADE;

ALTER TABLE "participation"
ADD FOREIGN KEY ("user_id") REFERENCES "user" ("id") ON DELETE CASCADE ON UPDATE CASCADE;