add guide for setting up a new host

new-host.md

@@ -0,0 +1,14 @@
+# Bare setup
+
+1. On the new host, copy [the host SSH key](/etc/ssh/ssh_host_ed25519_key.pub) to another host
+2. On that host, add the key to [secrets.nix](./secrets.nix) and run `agenix -r` to rekey them.
+3. `git push`, `git pull`
+4. On the new host, run `rebuild .#<HOSTNAME>`
+
+# Services
+
+## Tailscale
+
+1. Go to [localhost:8384](http://localhost:8384) and copy the device ID.
+2. Create a new machine entry in the [syncthing module](./modules/network/syncthing.nix).
+3. Add the new device to folders.