docs(doc/userguide.md): tweak Debian installation

Add note about `kvm` kernel module and Unix group.

Add step to create log directory.

Signed-off-by: Lars Wirzenius <liw@liw.fi>

doc/userguide.md

@@ -168,6 +168,9 @@ repository for a list.
   - `curl -sSf https://radicle.xyz/install | sh`
   - `rad auth`
   - `rad node start`
+* Make sure the `kvm-intel` or `kvm-amd` kernel module is loaded, so
+  that VM hardware acceleration works. You may need to add your user
+  to the `kvm` group.
 * Make sure the node has at least a test repository:
   - `rad seed rad:z28U8KUBvVSMQc13NydX3LBDsdEdQ`
 * Install relevant software from `deb` packages on <http://apt.liw.fi/>:
@@ -224,6 +227,9 @@ log: /home/_rad/radicle-ci-ambient.log
 base_url: "https://ci0.liw.fi//ambient-log"
 ~~~
 
+* Create `/srv/http` with write permission for your user:  
+  `sudo install -d /srv/http -o $USER -g $USER`
+
 * Start the CI broker in the foreground:
   - `cib --config ci-broker.yaml --log-level info process-events`
 * In another terminal or shell sessions, trigger a run: