Add user service

frontend/services/application/user.service.ts

@@ -0,0 +1,23 @@
+import { UserItem } from '@/models/user'
+import { UserItemListRepository } from '@/repositories/user/interface'
+
+export class UserDTO {
+  id: number
+  username: string
+
+  constructor(item: UserItem) {
+    this.id = item.id
+    this.username = item.username
+  }
+}
+
+export class UserApplicationService {
+  constructor(
+    private readonly repository: UserItemListRepository
+  ) {}
+
+  public async list(query: string): Promise<UserDTO[]> {
+    const items = await this.repository.list(query)
+    return items.map(item => new UserDTO(item))
+  }
+}