Resolve "Configure MongoDB Connection"

Implemented connectDB, as described in #3 (closed); 1st commit introduced the check if connected to DB and make collections, 2nd commit made it fit the requirements and improved the code by adding error handling.

Closes #6 (closed)

mongodb.js

@@ -6,19 +6,9 @@ async function connectDB() {
     // Connect using the MongoDB URI from environment variables
     const conn = await mongoose.connect(process.env.MONGO_URI || "mongodb://127.0.0.1:27017/todo_app");
     console.log(`MongoDB connected: ${conn.connection.host}`);
-
-    // Get the database object from the connection
-    const db = conn.connection.db;
-
-    // Check if the collections exist and create them if not
-    await db.createCollection('users');
-    await db.createCollection('todos');
-    await db.createCollection('global');
-
-    console.log('Collections created successfully!');
   } catch (err) {
     console.error(`Error: ${err.message}`);
-    process.exit(1); // Exit the process with failure if the connection or collection creation fails
+    process.exit(1); // Exit the process with failure if the connection fails
   }
 }