Add provider autodetection for hetzner (#174)

nixos-infect

@@ -4,6 +4,12 @@
 
 set -e -o pipefail
 
+autodetectProvider() {
+  if [ -e /etc/hetzner-build ]; then
+    PROVIDER="hetznercloud"
+  fi
+}
+
 makeConf() {
   # Skip everything if main config already present
   [[ -e /etc/nixos/configuration.nix ]] && return 0
@@ -375,6 +381,10 @@ infect() {
   /nix/var/nix/profiles/system/bin/switch-to-configuration boot
 }
 
+if [ ! -v PROVIDER ]; then
+  autodetectProvider
+fi
+
 [ "$PROVIDER" = "digitalocean" ] && doNetConf=y # digitalocean requires detailed network config to be generated
 [ "$PROVIDER" = "lightsail" ] && newrootfslabel="nixos"
 if [[ "$PROVIDER" = "digitalocean" ]] || [[ "$PROVIDER" = "servarica" ]] || [[ "$PROVIDER" = "hetznercloud" ]]; then