New scale action for jobs (and a convenience task group method)

ui/app/adapters/job.js

@@ -68,4 +68,20 @@ export default class JobAdapter extends WatchableNamespaceIDs {
       },
     });
   }
+
+  scale(job, group, count, reason) {
+    const url = addToPath(this.urlForFindRecord(job.get('id'), 'job'), '/scale');
+    return this.ajax(url, 'POST', {
+      data: {
+        Count: count,
+        Reason: reason,
+        Target: {
+          Group: group,
+        },
+        Meta: {
+          Source: 'nomad-ui',
+        },
+      },
+    });
+  }
 }

ui/app/models/job.js

@@ -245,6 +245,10 @@ export default class Job extends Model {
     return promise;
   }
 
+  scale(group, count, reason = 'Manual scaling event from the Nomad UI') {
+    return this.store.adapterFor('job').scale(this, group, count, reason);
+  }
+
   setIdByPayload(payload) {
     const namespace = payload.Namespace || 'default';
     const id = payload.Name;

ui/app/models/task-group.js

@@ -53,4 +53,8 @@ export default class TaskGroup extends Fragment {
   get summary() {
     return maybe(this.get('job.taskGroupSummaries')).findBy('name', this.name);
   }
+
+  scale(count, reason) {
+    return this.job.scale(this.name, count, reason);
+  }
 }