Add process.env.PORT to get default application port

src/server.js

@@ -8,9 +8,8 @@ const log = require(`${libs}/log`)(module);
 
 const app = require(`${libs}/app`);
 
-app.set('port', config.get('port') || 3000);
+app.set('port', process.env.PORT || config.get('port') || 3000);
 
 const server = app.listen(app.get('port'), () => {
-    debug(`Express server listening on port ${server.address().port}`);
-    log.info(`Express server listening on port ${config.get('port')}`);
+    log.info(`Express server listening on port ${server.address().port}`);
 });