added first lxc host "test-nix"

README.md

@@ -48,6 +48,20 @@ Show exported home configurations:
 nix eval --apply builtins.attrNames .#homeConfigurations
 ```
 
+### Testing
+
+These commands would are useful for debugging
+
+```shell
+SYSTEM=lxc
+
+# Just evaluate (fast, catches config errors)
+nix eval .#nixosConfigurations.${SYSTEM}.config.system.build.toplevel
+
+# Full build (slower, produces a bootable system)
+nix build .#nixosConfigurations.${SYSTEM}.config.system.build.toplevel
+```
+
 ### Remote Deploy
 
 ```shell