역할 디비 기능 추가

src/db/index.ts

 export * as userDb from "./user.db";
+export * as roleDb from "./role.db";

src/db/role.db.ts

+import { Role, User } from "../models";
+
+export const findRoleById = async (roleId: string) => {
+  const role = await Role.findById(roleId);
+  return role;
+};
+
+export const findRoleByName = async (roleName: string) => {
+  const role = await Role.findOne({ name: roleName });
+  return role;
+};
+
+export const findRoleByUserId = async (userId: string) => {
+  const user = await User.findById(userId).populate("role");
+  const role = user?.get("role");
+  return role;
+};
+
+export const getAllRoles = async () => {
+  const roles = await Role.find({});
+  return roles;
+};