update nyancat rainbow id's

init.lua

@@ -572,9 +572,9 @@ columnia.register_column_ia("marble", "darkage:marble",
          default.node_sound_stone_defaults()
          )
 
-columnia.register_column_ia("nyancat_rainbow", "default:nyancat_rainbow",
+columnia.register_column_ia("nyancat_rainbow", "nyancat:rainbow",
          {cracky=3},
-         {"default_nc_rb.png"},
+         {"nyancat_rainbow.png"},
          "Rainbow Column",
          "Rainbow Top",
          "Rainbow Bottom",