postgres: add c3nav, gradient (#399)

* postgres: add c3nav

* postgres: add gradient

* github/workflows/flake-check.yaml: remove exact nix version

Author: SuperSandro2000

.github/workflows/flake-check.yaml

@@ -25,7 +25,7 @@ jobs:
 
           # Do we need this?
           # - repo: NuschtOS/nuschtpkgs
-          #   branch: nixos-25.11
+          #   branch: nixos-26.05
           - repo: NuschtOS/nuschtpkgs
             branch: backports-26.05
           - repo: NuschtOS/nuschtpkgs
@@ -39,8 +39,6 @@ jobs:
 
       - name: Install Nix
         uses: nixbuild/nix-quick-install-action@v35
-        with:
-          nix_version: 2.31.2
 
       - uses: nix-community/cache-nix-action@v7
         with:

modules/postgres.nix

@@ -316,8 +316,10 @@ in
         ];
         upgrade.stopServices = with config.services; lib.mkMerge [
           (lib.mkIf (atuin.enable && atuin.database.createLocally) [ "atuin" ])
+          (lib.mkIf (c3nav.enable && pretalx.settings.database.host == "/run/postgresql" or false) [ "c3nav-web" "c3nav-worker" ])
           (lib.mkIf (gancio.enable && gancio.settings.db.dialect == "postgres") [ "gancio" ])
           (lib.mkIf (gitea.enable && gitea.database.socket == "/run/postgresql") [ "gitea" ])
+          (lib.mkIf (gradient.enable && gradient.configurePostgres) [ "gradient-server" ])
           (lib.mkIf (grafana.enable && grafana.settings.database.host == "/run/postgresql") [ "grafana" ])
           (lib.mkIf (healthchecks.enable && healthchecks.settings.DB_HOST == "/run/postgresql") [ "healthchecks" ])
           (lib.mkIf (hedgedoc.enable && hedgedoc.settings.db.host == "/run/postgresql") [ "hedgedoc" ])