Uncomment console.log in database

There were some remarks about console.logs causing issues with 
pg-native, so I temporarily commented-out the console.logs. Anyway, 
these console.logs do not seem to be an issue.

See: 
sequelize/sequelize#3781 (comment)

Author: FinnWoelm

database/index.ts

@@ -39,9 +39,9 @@ const db = {
 (async () => {
   try {
     await sequelize.authenticate();
-    // console.log('Database connection has been established successfully.');
+    console.log('Database connection has been established successfully.');
   } catch (error) {
-    // console.error('Unable to connect to the database:', error);
+    console.error('Unable to connect to the database:', error);
   }
 })();