Update README TSL cert renewal instructions

README.md

@@ -96,6 +96,20 @@ SSH into server admin account and run:
     $ cd www
     $ dehydrated --config config -c
 
+Then restart the OpenResty service:
+
+    $ sudo service openresty restart
+
+#### automate TSL cert renewal with cron
+
+Open root's crontab:
+
+    $ sudo crontab -e
+
+Add the following line, then save and exit:
+
+    19 4 1 * * /usr/bin/dehydrated --config /var/www/config --cron >/dev/null 2>&1 && /usr/bin/systemctl restart openresty.service
+
 ## gotchas
 
 ### What is error `cosmo failed: [string "..."]:62: cannot resume dead coroutine`?
@@ -119,3 +133,11 @@ Delete your `.sitegen_cache` file.
 * use sitecache with pandoc renderer
 * draft documents
 * treesitter highlighting for moonscript
+
+## todo
+
+* destroy a target ship by shooting them with the cannon
+* make corners not bouncy (leave them bouncy for now?)
+* wall entities
+* ship-ship collision
+* make ssh command?