make users non-secret

The default case was actually catastrophically bad for any actual deployment
since it would just lock everyone out of all the systems.

morph/grid/testing/grid.nix

@@ -6,12 +6,7 @@ import ../../lib/make-grid.nix {
   config = ./config.json;
   nodes = cfg:
   let
-    importDef = default: path: (
-      if builtins.pathExists path
-      then import path
-      else default
-    );
-    sshUsers = importDef {} ./secrets/staging-users.nix;
+    sshUsers = import ./users.nix;
   in {
     "payments" = import ../../lib/make-issuer.nix ({
       publicIPv4 = "18.197.42.120";

morph/grid/testing/users.nix

+let key = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIGN4VQm3BIQKEFTw6aPrEwNuShf640N+Py2LOKznFCRT exarkun@bottom";
+in { "root" = key; jcalderone = key; }