fix: add explicit async and inverse relationship options in test app

tests/dummy/app/models/group.ts

@@ -16,10 +16,12 @@ export default class GroupModel extends Model {
   @attr('string')
   declare public name: string;
 
-  @hasMany('user')
+  @hasMany('user', { async: true, inverse: 'groups' })
   declare public members: DS.PromiseManyArray<UserModel>;
 
   @hasMany('post', {
+    async: true,
+    inverse: 'group',
     isRealtime: true,
 
     filter(reference: Query) {

tests/dummy/app/models/post.ts

@@ -20,13 +20,14 @@ export default class PostModel extends Model {
   @attr('timestamp')
   declare public createdOn: TimestampTransform;
 
-  @belongsTo('user')
+  @belongsTo('user', { async: true, inverse: 'posts' })
   declare public author: DS.PromiseObject<UserModel>;
 
-  @belongsTo('group')
+  @belongsTo('group', { async: true, inverse: 'posts' })
   declare public group: DS.PromiseObject<GroupModel>;
 
   @belongsTo('user', {
+    async: true,
     inverse: null,
 
     buildReference(db: Firestore) {

tests/dummy/app/models/user.ts

@@ -13,10 +13,10 @@ export default class UserModel extends Model {
   @attr('string')
   declare public name: string;
 
-  @hasMany('group')
+  @hasMany('group', { async: true, inverse: 'members' })
   declare public groups: DS.PromiseManyArray<GroupModel>;
 
-  @hasMany('post')
+  @hasMany('post', { async: true, inverse: 'author' })
   declare public posts: DS.PromiseManyArray<PostModel>;
 }