update host list

hosts/configuration.nix

@@ -34,6 +34,8 @@
       "100.64.0.1" = [ "elnu" ];
       "100.64.0.2" = [ "elnuhub" ];
       "100.64.0.3" = [ "elnudrop" ];
+      "100.64.0.4" = [ "pang13" ];
+      "100.64.0.5" = [ "elnucentre" ];
     };
   };