nix/hm: add extraEnvironment (#533)

* nix: add extraEnvironment in home-manager

This PR enables users to easily add environment variables to make systemd services work properly in all use cases. #390

* Update README.md

* Update README.md

* fix

* Update hm-module.nix

* Update hm-module.nix

* extraEnvironment to environment

* Update README.md

* [CI] chore: update flake

* fix

---------

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

README.md

@@ -223,6 +223,7 @@ programs.caelestia = {
     };
     paths.wallpaperDir = "~/Images";
   };
+  environment = [];
   cli = {
     enable = true; # Also add caelestia-cli to path
     settings = {

nix/hm-module.nix

@@ -43,6 +43,14 @@ in {
         default = "";
         description = "Caelestia shell extra configs written to shell.json";
       };
+      environment = mkOption {
+        type = types.listOf types.str;
+        description = "Extra Environment variables to pass to the Caelestia shell systemd service.";
+        default = [ ];
+        example = [
+          "QT_QPA_PLATFORMTHEME=gtk3"
+        ];
+      };
       cli = {
         enable = mkEnableOption "Enable Caelestia CLI";
         package = mkOption {
@@ -87,7 +95,8 @@ in {
           TimeoutStopSec = "5s";
           Environment = [
             "QT_QPA_PLATFORM=wayland"
-          ];
+          ]
+          ++ cfg.environment;
 
           Slice = "session.slice";
         };