clanService/prometheus: init monitoring system

modules/clan/prometheus/flake-module.nix

@@ -0,0 +1,19 @@
+{ self, inputs, ... }:
+let
+  module = ./default.nix;
+in
+{
+  clan.modules = {
+    prometheus = module;
+  };
+  perSystem =
+    { ... }:
+    {
+      clan.nixosTests.service-prometheus = {
+        imports = [ ./tests/vm/default.nix ];
+        _module.args = { inherit self inputs; };
+
+        clan.modules."@clan/prometheus" = module;
+      };
+    };
+}