docs(json-api-nestjs-microorm): Change readme

Author: klerick

libs/json-api/json-api-nestjs-microorm/README.md

@@ -18,3 +18,36 @@ export type MicroOrmParam = {
 };
 
 ```
+
+## NOTE: MikroORM Default Named Context Issue in NestJS
+
+[@mikro-orm/nestjs](https://github.com/mikro-orm/nestjs) does not create a [default named context](https://github.com/mikro-orm/nestjs/discussions/214).
+
+As a result, the module initialization behaves differently depending on whether a single or multiple connections are used. 
+More specifically, the [dependency injection token for MikroORM differs](https://github.com/mikro-orm/nestjs/issues/213) between one and multiple database connections.
+
+To maintain a consistent JSON:API module configuration across different database adapters, 
+I decided **not to add extra conditional checks** in the setup.
+
+For everything to work correctly, @mikro-orm/nestjs should be integrated using the following module:
+👉 [MicroORM Database Module](https://github.com/klerick/nestjs-json-api/blob/master/libs/microorm-database/src/lib/micro-orm-database.module.ts).
+
+```typescript
+import ormConfig from './config';
+
+// need set contextName and registerRequestContext
+export const config: Options = {
+  contextName: 'default',
+  registerRequestContext: false,
+  ...ormConfig,
+};
+
+@Module({
+  imports: [MikroOrmModule.forRoot(config), MikroOrmModule.forMiddleware()],
+  exports: [MikroOrmCoreModule],
+})
+export class MicroOrmDatabaseModule {}
+```
+
+
+