feat: add user submission functionality

src/modules/auth/guards/optional-jwt.guard.ts

@@ -0,0 +1,10 @@
+import { User } from '@/modules/users/entities/user.entity';
+import { Injectable } from '@nestjs/common';
+import { AuthGuard } from '@nestjs/passport';
+
+@Injectable()
+export class OptionalJwtGuard extends AuthGuard('jwt') {
+  handleRequest<TUser = User>(err: any, user: TUser): TUser | null {
+    return user ?? null;
+  }
+}