Get rid of redundant DB shutdown and move it to main()

app/server/src/db/mongo.js

@@ -36,10 +36,4 @@ mongooseInstance_
     });
 
 
-process.on( 'exit', async ()=>{
-    const dbClient = await mongooseInstance_;
-    dbClient.disconnect();
-});
-
-
 module.exports = mongooseInstance_;

app/server/src/index.js

@@ -44,21 +44,24 @@ app.use(errorRoutes);
 
 
 (async function main(){
+    process.on( 'exit', async ()=>{
+        const dbClient = await dbClientInstance_;
+        await dbClient.disconnect();
+    });
+
     try{
         const server = http.createServer( app );
         await new Promise( (__ful, rej__ )=>{
-            server.listen(port, function(){
-                console.log( `ToDo server is up on port ${ port }`);
+            server.listen( port, ()=>{
+                console.log( `ToDo server is up & bound to port ${ port }` );
                 __ful();
-            }).on( 'error', rej__);
+            }).on( 'error', rej__ );
         });
 
-        process.on( 'SIGINT', async ()=>{
+        process.on( 'SIGINT', ()=>{
             server.close( ()=>{
-                console.log( 'Shutting ToDo server' );
+                console.log( 'Shutting down ToDo server' );
             });
-            const dbClient = await dbClientInstance_;
-            await dbClient.disconnect();
             process.exit( 0 );
         });
     }catch( err ){