Add postgresql module

hosts/vps1/default.nix

@@ -43,7 +43,8 @@
 
   services.openssh.settings.PermitRootLogin = lib.mkForce "prohibit-password";
 
-  modules = {
+  modules = rec {
+    databases.postgresql.enable = true;
     services = {
       borgmatic = {
         enable = true;
@@ -61,7 +62,10 @@
       };
       gitea.enable = true;
       headscale.enable = true;
-      matrix-synapse.enable = true;
+      matrix-synapse = {
+        enable = true;
+        usePostgresql = databases.postgresql.enable;
+      };
       nginx.enable = true;
       photoprism.enable = true;
     };