fix: add ConfigModule to imports in CategoriesModule

backend/src/api/categories/categories.module.ts

@@ -2,8 +2,10 @@ import { Module } from '@nestjs/common';
 import { CategoriesService } from './categories.service';
 import { CategoriesController } from './categories.controller';
 import { PrismaService } from 'src/prisma/prisma.service';
+import { ConfigModule } from '@nestjs/config';
 
 @Module({
+  imports: [ConfigModule],
   controllers: [CategoriesController],
   providers: [CategoriesService, PrismaService],
 })