add user group components

server/src/entity/user-group.ts

@@ -6,6 +6,7 @@ import {
   JoinTable,
 } from 'typeorm';
 import { UserRole } from './user-role';
+import { IsString } from 'class-validator';
 
 @Entity()
 export class UserGroup {
@@ -13,6 +14,7 @@ export class UserGroup {
   id: number;
 
   @Column({ unique: true })
+  @IsString()
   name: string;
 
   @ManyToMany(() => UserRole)