*: set isSystemUser or isNormalUser

This is a requirement for nixpkgs 21.05, or else evaluation will fail
with:

Exactly one of users.users.${name}.isSystemUser and users.users.${name}.isNormalUser must be set.

1 files changed, 1 insertions, 0 deletions

diff --git a/krebs/3modules/exim.nix b/krebs/3modules/exim.nix
index 83d88cb0..972c7f43 100644
--- a/krebs/3modules/exim.nix
+++ b/krebs/3modules/exim.nix
@@ -78,6 +78,7 @@ in {
         inherit (cfg.user) home name uid;
         createHome = true;
         group = cfg.group.name;
+        isSystemUser = true;
       };
     };
   };