feat: add adapter for fetching discount codes using event identifier (#3311)

Author: abhinavk96

app/adapters/discount-code.js

@@ -0,0 +1,13 @@
+import ApplicationAdapter from './application';
+import ENV from 'open-event-frontend/config/environment';
+
+export default ApplicationAdapter.extend({
+
+  urlForQueryRecord(query) {
+    if (query && query.code && query.eventIdentifier) {
+      return `${ENV.APP.apiHost}/v1/events/${query.eventIdentifier}/discount-codes/${query.code}`;
+    } else {
+      return this._super(...arguments);
+    }
+  }
+});