Exclude .git and vm disk images in deployment

Fixes #8 (at least good enough for now)

deploy.nix

@@ -19,7 +19,19 @@ let
             url = https://github.com/NixOS/nixpkgs;
             shallow = true;
           };
-          config.file = toString ./.;
+          config.file = {
+            path = toString ./.;
+            filters = [
+              {
+                type = "exclude";
+                pattern = ".git";
+              }
+              {
+                type = "exclude";
+                pattern = "*.qcow2";
+              }
+            ];
+          };
           nixos-config.symlink = "config/machines/${hostname}/configuration.nix";
           secrets.pass = {
             dir = toString ~/.password-store;