updates README (adds self-destroy screenshot)

README.md

@@ -143,3 +143,20 @@ It would be awesome to get tooling for these to tootctl. That said, I'm not
 entirely sure if destroying the entities is necessary before downloading them
 again, and perhaps we could use remove_entity_cache instead. I'm not very well
 acquainted with the codebase.
+
+### instance self-destroy
+
+```console
+$ bin/tootctl self-destruct
+Type in the domain of the server to confirm: fedi.oe7drt.com
+This operation WILL NOT be reversible. It can also take a long time.
+While the data won't be erased locally, the server will be in a BROKEN STATE afterwards.
+A running Sidekiq process is required. Do not shut it down until queues clear.
+Are you sure you want to proceed? yes
+Do NOT interrupt this process...
+Queued 16232 items into Sidekiq for 4 accounts
+Wait until Sidekiq processes all items, then you can shut everything down and delete the data
+```
+
+![above console output as screenshot](destroy.png)
+