Add information about breaking changes in Angular 8 and Angular CLI 8.1

README.MD

@@ -82,6 +82,29 @@ import { JsonApiModule } from 'angular2-jsonapi';
 export class AppModule { }
 ```
 
+### Angular CLI configuration (for CLI 8.1+)
+
+Beginning from Angular CLI 8.1 the `tsconfig.json` does not sets the `emitDecoratorMetadata` option (see https://blog.ninja-squad.com/2019/07/03/angular-cli-8.1/#typescript-configuration-changes). But we need it to read the metadata from the models. So make sure to update your `tsconfig.json`:
+
+```json
+{
+  "compilerOptions": {
+    "emitDecoratorMetadata": true,
+  }
+}
+```
+
+### Notice for `es2015` compilation
+
+Beginning with Angular 8 the default compile target will be `es2015` (in `tsconfig.json`). 
+Make sure to add this line in your `src/polyfills.ts` as we need it to read metadata from the models:
+
+```typescript
+import 'core-js/proposals/reflect-metadata';
+```
+
+**Warning**: If you have circular dependencies in your model definitions (see https://github.com/ghidoz/angular2-jsonapi/issues/236#issuecomment-519473153 for example), you need to change the compile target to `es5` as this lead to runtime errors `ReferenceError: Cannot access 'x' before initialization` (see https://github.com/angular/angular/issues/30106#issuecomment-497699838).
+
 ## Usage
 
 ### Configuration