refactor: cleaned up nixos dir

nixos/modules/services/postgresql/default.nix

@@ -0,0 +1,60 @@
+{ flake, ... }:
+let
+  inherit (flake.config.machines.devices)
+    server
+    ;
+  inherit (flake.config.services.instances)
+    postgresql
+    ;
+
+  service = postgresql;
+in
+{
+  services = {
+    postgresqlBackup = {
+      enable = true;
+      location = service.paths.path0;
+      databases = [
+        "mastodon"
+        "nextcloud"
+        "peertube"
+        "forgejo"
+      ];
+    };
+    postgresql = {
+      enable = true;
+    };
+  };
+  networking = {
+    firewall = {
+      allowedTCPPorts = [
+        service.ports.port0
+      ];
+    };
+  };
+
+  fileSystems."/var/lib/postgresql" = {
+    device = service.paths.path0;
+    fsType = "none";
+    options = [
+      "bind"
+    ];
+    depends = [
+      server.storage0.mount
+    ];
+  };
+
+  systemd.tmpfiles.rules = [
+    "Z ${service.paths.path0} 700 ${service.name} ${service.name} -"
+  ];
+
+  users.users.${service.name}.extraGroups = [
+    "nextcloud"
+    "mastodon"
+    "forgejo"
+  ];
+
+  system.activationScripts.postgresCommands = ''
+    chown -R ${service.name}:${service.name} ${service.paths.path0}
+  '';
+}