docs: add @nestjs/typeorm issue 86 solution in sql.md

Author: ppodds

content/techniques/sql.md

@@ -576,6 +576,21 @@ export class AppModule {}
 
 > warning **Notice** If you don't set the `name` for a connection, its name is set to `default`. Please note that you shouldn't have multiple connections without a name, or with the same name, otherwise they will get overridden.
 
+> warning **Notice** If you are using `TypeOrmModule.forRootAsync`, you have to set connection name outside `useFactory`. For example:
+> ```typescript
+> TypeOrmModule.forRootAsync({
+>   name: 'albumsConnection',
+>   useFactory: (config: ConfigService) =>
+>     ({
+>       ...config.get('db'),
+>       host: 'album_db_host',
+>       entities: [Album],
+>     } as TypeOrmModuleOptions),
+>   inject: [ConfigService],
+> }),
+> ```
+> [@nestjs/typeorm issue](https://github.com/nestjs/typeorm/issues/86)
+
 At this point, you have `User` and `Album` entities registered with their own connection. With this setup, you have to tell the `TypeOrmModule.forFeature()` method and the `@InjectRepository()` decorator which connection should be used. If you do not pass any connection name, the `default` connection is used.
 
 ```typescript