📝 Add docstrings to database-models

Docstrings generation was requested by @ailearningguy.

* #3 (comment)

The following files were modified:

* `lib/mongodb.ts`

Author: coderabbitai[bot]

lib/mongodb.ts

@@ -33,6 +33,13 @@ if (!cached) {
   };
 }
 
+/**
+ * Get or establish a cached Mongoose connection to the configured MongoDB URI.
+ *
+ * Reuses an existing cached connection when available; otherwise establishes a new connection and caches it for subsequent calls.
+ *
+ * @returns The established Mongoose connection
+ */
 async function connectDB() {
   // If a connection is already cached, use it
   if (cached.conn) {
@@ -52,4 +59,4 @@ async function connectDB() {
   return cached.conn;
 }
 
-export default connectDB;
+export default connectDB;