Modernized the app with app structure from Stage Manager

config/defaults.yaml

@@ -1,3 +1,7 @@
 ldap:
   server_url: 'ldap://ldap.example.com'
   port: 389
+
+server:
+  address: '127.0.0.1'
+  port: 4567

config/puma.rb

@@ -0,0 +1,6 @@
+# Load application config
+require './app/config.rb'
+$conf = Config.new(File.join(__dir__, 'config/config.yaml'))
+
+bind_address = "tcp://#{$conf.get('server.address')}:#{$conf.get('server.port')}"
+bind bind_address