feat: 🎸 add host set management support for tagets in API layer

addons/api/addon/models/fragment-host-set.js

@@ -0,0 +1,16 @@
+import Fragment from 'ember-data-model-fragments/fragment';
+import { attr } from '@ember-data/model';
+
+export default class FragmentHostSetModel extends Fragment {
+
+  // =attributes
+
+  @attr('string', {
+    description: 'ID of the related host set'
+  }) host_set_id;
+
+  @attr('string', {
+    description: 'ID of the catalog to which the host set belongs'
+  }) host_catalog_id;
+
+}

addons/api/addon/models/target.js

@@ -1,3 +1,39 @@
 import GeneratedTargetModel from '../generated/models/target';
+import { fragmentArray } from 'ember-data-model-fragments/attributes';
 
-export default class TargetModel extends GeneratedTargetModel {}
+export default class TargetModel extends GeneratedTargetModel {
+
+  // =attributes
+
+  @fragmentArray('fragment-host-set', {readOnly: true}) host_sets;
+
+  // =methods
+
+  /**
+   * Saves the `host_set_ids` array on the via the `set-hosts` method.
+   * See serializer and adapter for more information.
+   * @param {object} options
+   * @param {object} options.adapterOptions
+   * @return {Promise}
+   */
+  saveHostSets(options={ adapterOptions: {} }) {
+    const defaultOptions = {
+      adapterOptions: {
+        method: 'set-host-sets',
+        serializeHostSets: true
+      }
+    };
+    // There is no "deep merge" in ES.
+    // All of this nonsense is here to ensure we get
+    // a decent merge of `adapterOptions`.
+    return this.save({
+      ...defaultOptions,
+      ...options,
+      adapterOptions: {
+        ...defaultOptions.adapterOptions,
+        ...options.adapterOptions
+      }
+    });
+  }
+
+}