feat: add user operations to backend

backend/src/auth/dto/authSignIn.dto.ts

@@ -1,8 +1,13 @@
-import { PickType } from "@nestjs/swagger";
+import { PickType } from "@nestjs/mapped-types";
+import { IsEmail, IsOptional, IsString } from "class-validator";
 import { UserDTO } from "src/user/dto/user.dto";
 
-export class AuthSignInDTO extends PickType(UserDTO, [
-  "username",
-  "email",
-  "password",
-] as const) {}
+export class AuthSignInDTO extends PickType(UserDTO, ["password"] as const) {
+  @IsEmail()
+  @IsOptional()
+  email: string;
+
+  @IsString()
+  @IsOptional()
+  username: string;
+}