Modernize ember-cli-mirage usage

tests/dummy/mirage/config.js

@@ -1,3 +1,21 @@
-export default function() {
-  this.get('/cars');
+import { applyEmberDataSerializers, discoverEmberDataModels } from "ember-cli-mirage";
+import { createServer } from 'miragejs';
+
+export default function(config) {
+  const finalConfig = {
+    ...config,
+
+    models: {
+      ...discoverEmberDataModels(),
+      ...config.models,
+    },
+
+    serializers: applyEmberDataSerializers(config.serializers),
+
+    routes() {
+      this.get('/cars');
+    },
+  };
+
+  return createServer(finalConfig);
 }

tests/dummy/mirage/serializers/application.js

@@ -1,5 +1,5 @@
-import { ActiveModelSerializer } from 'ember-cli-mirage';
+import { EmberDataSerializer } from "ember-cli-mirage";
 
-export default ActiveModelSerializer.extend({
+export default EmberDataSerializer.extend({
   serializeIds: 'always',
 });