update readme

README.md

@@ -15,6 +15,25 @@ docker run \
     -d sneak/ipfs-ubuntu-mirror
 ```
 
+# requires
+
+requires apt-transport-ipfs to use:
+
+https://github.com/JaquerEspeis/apt-transport-ipfs
+
+# see also
+
+best-effort usually-up non-ha ipns pointer to ubuntu mirror:
+
+`ipfs:/ipns/Qme4tKNduvAgQKN6nKjyH7KjyMdJwyPHfeVMp2EUS6b3J1`
+
+viz:
+
+```
+NS=Qme4tKNduvAgQKN6nKjyH7KjyMdJwyPHfeVMp2EUS6b3J1
+echo 'deb ipfs:/ipns/$NS bionic main restricted universe multiverse' > /etc/apt/sources.list
+```
+
 # maintainer
 
 Jeffrey Paul <sneak@sneak.berlin>