added some first contributing guidelines and changed the config skeleton

flake.lock

@@ -33,6 +33,24 @@
         "type": "indirect"
       }
     },
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1685518550,
+        "narHash": "sha256-o2d0KcvaXzTrPRIo0kOLV0/QXHhDQ5DTi+OxcjO8xqY=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "a1720a10a6cfe8234c0e93907ffe81be440f4cef",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
     "impermanence": {
       "locked": {
         "lastModified": 1697303681,
@@ -151,12 +169,35 @@
         "type": "github"
       }
     },
+    "pre-commit-hooks": {
+      "inputs": {
+        "flake-compat": [],
+        "flake-utils": "flake-utils",
+        "gitignore": [],
+        "nixpkgs": [],
+        "nixpkgs-stable": []
+      },
+      "locked": {
+        "lastModified": 1699271226,
+        "narHash": "sha256-8Jt1KW3xTjolD6c6OjJm9USx/jmL+VVmbooADCkdDfU=",
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "rev": "ea758da1a6dcde6dc36db348ed690d09b9864128",
+        "type": "github"
+      },
+      "original": {
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "flake-parts": "flake-parts",
         "impermanence": "impermanence",
         "nixos-mailserver": "nixos-mailserver",
         "nixpkgs": "nixpkgs",
+        "pre-commit-hooks": "pre-commit-hooks",
         "sops-nix": "sops-nix"
       }
     },
@@ -181,6 +222,21 @@
         "type": "github"
       }
     },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
     "utils": {
       "locked": {
         "lastModified": 1605370193,