Hydra: init spec file

hydra.json

@@ -0,0 +1,12 @@
+{
+  "enabled": 1,
+  "hidden": 1,
+  "type": 1,
+  "flake": "git+https://git.sr.ht/~ehmry/genodepkgs",
+  "description": "Genode Nix packages",
+  "checkinterval": 300,
+  "schedulingshares": 100,
+  "enableemail": false,
+  "emailoverride": "",
+  "keepnr": 3
+}