add postgres container

hosts/sql/default.nix

@@ -0,0 +1,31 @@
+{ ... }:
+
+{
+  imports = [
+    ../common.nix
+    ../../services/openssh.nix
+  ];
+
+  networking = {
+    hostName = "sql";
+    firewall = {
+      # TODO: add postgres from internal network
+    };
+  };
+
+  services = {
+    openssh.banner = ''
+                     ___
+                    /\_ \
+        ____     __ \//\ \
+       /',__\  /'__`\ \ \ \
+      /\__, `\/\ \L\ \ \_\ \_
+      \/\____/\ \___, \/\____\
+       \/___/  \/___/\ \/____/
+                    \ \_\
+                     \/_/
+    '';
+  };
+
+  system.stateVersion = "25.11";
+}