Fix service restarter test

README.md

@@ -120,11 +120,21 @@ runner can write to is enough:
 sudo mkdir -p /var/www/html/heos
 sudo chown "$(id -un)": /var/www/html/heos
 
-echo "$(id -un) ALL=(ALL) NOPASSWD: /usr/bin/systemctl restart heos-panel" \
+echo "$(id -un) ALL=(ALL) NOPASSWD: $(command -v systemctl) restart heos-panel" \
   | sudo tee /etc/sudoers.d/heos-panel
 sudo chmod 440 /etc/sudoers.d/heos-panel
 ```
 
+Run those **as the user the runner runs as**, not as yourself — the first
+step of the workflow prints who that is. Two things in that sudoers line are
+easy to get wrong, and the workflow checks both before it deploys anything,
+printing the line back at you with the right values filled in:
+
+- the user has to be the runner's, and
+- the path has to be the one `sudo` resolves from `PATH`. It compares that
+  string against the sudoers line without following symlinks, so on a system
+  where `/bin` links to `/usr/bin` the two spellings are not interchangeable.
+
 Then push. That first run deploys the files and builds the virtualenv, and
 stops at the restart, because the service does not exist yet. Install it
 from the copy it just put there: