fix: auth issue with reading env var

src/auth/auth.module.ts

 import { Module } from '@nestjs/common';
 import { JwtModule } from '@nestjs/jwt';
 import { PassportModule } from '@nestjs/passport';
+import * as dotenv from 'dotenv';
 import { UsersModule } from '../users/users.module';
 import { AuthController } from './auth.controller';
 import { AuthService } from './auth.service';
 import { JwtStrategy } from './strategy/jwt.strategy';
+dotenv.config();
 
 @Module({
   imports: [
     UsersModule,
     PassportModule,
     JwtModule.register({
-      secret: `${process.env.JWT_SECRET}`,
+      secret: process.env.JWT_SECRET,
       signOptions: { expiresIn: '86400s' }, // 24h validity
     }),
   ],