feat: Introduce base model to implement created_at & updated_at logic

packages/backend/src/models/base.ts

@@ -0,0 +1,21 @@
+import { Model, QueryContext, ModelOptions } from 'objection';
+
+class Base extends Model {
+  created_at!: string;
+  updated_at!: string;
+
+  async $beforeInsert(queryContext: QueryContext) {
+    await super.$beforeInsert(queryContext);
+
+    this.created_at = new Date().toISOString();
+    this.updated_at = new Date().toISOString();
+  }
+
+  async $beforeUpdate(opt: ModelOptions, queryContext: QueryContext) {
+    await super.$beforeUpdate(opt, queryContext);
+
+    this.updated_at = new Date().toISOString();
+  }
+}
+
+export default Base;