docs(sql) Mention exporting repository providers

content/techniques/sql.md

@@ -180,6 +180,39 @@ export class PhotoService {
 
 > warning **Notice** Do not forget to import the `PhotoModule` into the root `ApplicationModule`.
 
+If you want to use the repository outside of the module which imports `TypeOrmModule.forFeature`, you'll need to re-export the providers generated by it.
+You can do this by exporting the whole module, like this:
+
+```typescript
+@@filename(photo.module)
+import { Module } from '@nestjs/common';
+import { TypeOrmModule } from '@nestjs/typeorm';
+import { Photo } from './photo.entity';
+
+@Module({
+  imports: [TypeOrmModule.forFeature([Photo])],
+  exports: [TypeOrmModule]
+})
+export class PhotoModule {}
+```
+
+Now if we import `PhotoModule` in `PhotoHttpModule`, we can use `@InjectRepository(Photo)` in the providers of the latter module. 
+
+```typescript
+@@filename(photo-http.module)
+import { Module } from '@nestjs/common';
+import { PhotoModule } from './photo.module';
+import { PhotoService } from './photo.service';
+import { PhotoController } from './photo.controller';
+
+@Module({
+  imports: [PhotoModule],
+  providers: [PhotoService],
+  controllers: [PhotoController]
+})
+export class PhotoHttpModule {}
+```
+
 #### Multiple databases
 
 Some of your projects may require multiple database connections. Fortunately, this can also be achieved with this module. To work with multiple connections, the first thing to do is to create those connections. In this case, the connection naming becomes **mandatory**.