refactor: refactor thread, message, and gap models to Typescript

Bug: twpowertools:230
Change-Id: I6729546ec4e84f4ef2e801a3c479b63c351008f9
diff --git a/src/models/Gap.js b/src/models/Gap.js
index 8c380b2..f5be276 100644
--- a/src/models/Gap.js
+++ b/src/models/Gap.js
@@ -1,4 +1,4 @@
-import ThreadModel from './Thread.js';
+import ThreadModel from './Thread.ts';
 
 export default class GapModel {
   constructor(data, thread) {