treewide: use attrs instead of list for types.loaOf options

nixos/modules/services/databases/cockroachdb.nix

@@ -171,17 +171,17 @@ in
 
     environment.systemPackages = [ crdb ];
 
-    users.users = optionalAttrs (cfg.user == "cockroachdb") (singleton
-      { name        = "cockroachdb";
+    users.users = optionalAttrs (cfg.user == "cockroachdb") {
+      cockroachdb = {
         description = "CockroachDB Server User";
         uid         = config.ids.uids.cockroachdb;
         group       = cfg.group;
-      });
+      };
+    };
 
-    users.groups = optionalAttrs (cfg.group == "cockroachdb") (singleton
-      { name = "cockroachdb";
-        gid  = config.ids.gids.cockroachdb;
-      });
+    users.groups = optionalAttrs (cfg.group == "cockroachdb") {
+      cockroachdb.gid = config.ids.gids.cockroachdb;
+    };
 
     networking.firewall.allowedTCPPorts = lib.optionals cfg.openPorts
       [ cfg.http.port cfg.listen.port ];

nixos/modules/services/databases/foundationdb.nix

@@ -341,17 +341,17 @@ in
 
     environment.systemPackages = [ pkg ];
 
-    users.users = optionalAttrs (cfg.user == "foundationdb") (singleton
-      { name        = "foundationdb";
+    users.users = optionalAttrs (cfg.user == "foundationdb") {
+      foundationdb = {
         description = "FoundationDB User";
         uid         = config.ids.uids.foundationdb;
         group       = cfg.group;
-      });
+      };
+    };
 
-    users.groups = optionalAttrs (cfg.group == "foundationdb") (singleton
-      { name = "foundationdb";
-        gid  = config.ids.gids.foundationdb;
-      });
+    users.groups = optionalAttrs (cfg.group == "foundationdb") {
+      foundationdb.gid = config.ids.gids.foundationdb;
+    };
 
     networking.firewall.allowedTCPPortRanges = mkIf cfg.openFirewall
       [ { from = cfg.listenPortStart;

nixos/modules/services/databases/influxdb.nix

@@ -182,15 +182,15 @@ in
         '';
     };
 
-    users.users = optional (cfg.user == "influxdb") {
-      name = "influxdb";
-      uid = config.ids.uids.influxdb;
-      description = "Influxdb daemon user";
+    users.users = optionalAttrs (cfg.user == "influxdb") {
+      influxdb = {
+        uid = config.ids.uids.influxdb;
+        description = "Influxdb daemon user";
+      };
     };
 
-    users.groups = optional (cfg.group == "influxdb") {
-      name = "influxdb";
-      gid = config.ids.gids.influxdb;
+    users.groups = optionalAttrs (cfg.group == "influxdb") {
+      influxdb.gid = config.ids.gids.influxdb;
     };
   };
 

nixos/modules/services/databases/memcached.nix

@@ -64,10 +64,9 @@ in
 
   config = mkIf config.services.memcached.enable {
 
-    users.users = optional (cfg.user == "memcached") {
-      name = "memcached";
-      description = "Memcached server user";
-      isSystemUser = true;
+    users.users = optionalAttrs (cfg.user == "memcached") {
+      memcached.description = "Memcached server user";
+      memcached.isSystemUser = true;
     };
 
     environment.systemPackages = [ memcached ];

nixos/modules/services/databases/neo4j.nix

@@ -650,8 +650,7 @@ in {
 
       environment.systemPackages = [ cfg.package ];
 
-      users.users = singleton {
-        name = "neo4j";
+      users.users.neo4j = {
         uid = config.ids.uids.neo4j;
         description = "Neo4j daemon user";
         home = cfg.directories.home;

nixos/modules/services/databases/virtuoso.nix

@@ -54,9 +54,8 @@ with lib;
 
   config = mkIf cfg.enable {
 
-    users.users = singleton
-      { name = virtuosoUser;
-        uid = config.ids.uids.virtuoso;
+    users.users.${virtuosoUser} =
+      { uid = config.ids.uids.virtuoso;
         description = "virtuoso user";
         home = stateDir;
       };