✨ feat: User Entity에 Guest여부를 나타내는 checkGuest Column추가

- User 테이블 속에 유저가 Guest인지 아닌지를 나타내는 flag checkGuest를 추가
Issue Resolved: #

Author: KWAKMANBO

back/src/domains/user/entity/user.entity.ts

@@ -16,6 +16,9 @@ export class User {
   @Column({ type: 'varchar', length: 10, name: 'role' })
   role: string;
 
+  @Column({ type: 'boolean', name: 'is_guest' })
+  checkGuest: boolean;
+
   @OneToMany(() => Reservation, (reservation) => reservation.user, { lazy: true })
   reservations: Promise<Reservation[]>;
 }