Implement files under /etc

nix/modules/default.nix

@@ -1,5 +1,6 @@
 { lib
 , pkgs
+, config
 , ...
 }:
 let
@@ -30,16 +31,42 @@ let
             '';
           })
       );
-in
-{
-  options = {
-    system-manager.services = lib.mkOption {
-      type = with lib.types; listOf str;
+
+  etcFiles = {
+    foo = {
+      text = ''
+        This is just a test!
+      '';
+      target = "foo_test";
+    };
+
+    "baz/bar/foo2" = {
+      text = ''
+        Another test!
+      '';
+      mode = "symlink";
+    };
+
+    foo3 = {
+      text = "boo!";
+      mode = "0700";
+      user = "root";
+      group = "root";
+    };
+
+    out-of-store = {
+      source = "/run/systemd/system/";
     };
   };
-
+in
+{
   config = {
-    system-manager.services = lib.attrNames services;
+    system.stateVersion = lib.trivial.release;
+    system-manager = {
+      etcFiles = lib.attrNames etcFiles;
+      services = lib.attrNames services;
+    };
+    environment.etc = etcFiles;
     systemd = { inherit services; };
   };
 }